diff --git a/example.c b/example.c
index 412affd..2e2afaa 100644
--- a/example.c
+++ b/example.c
@@ -14,8 +14,8 @@
  */
 
 /* This is an example of how to use libpng to read and write PNG files.
- * The file libpng-manual.txt is much more verbose then this.  If you have not
- * read it, do so first.  This was designed to be a starting point of an
+ * The file libpng-manual.txt is much more verbose then this.  If you have
+ * not read it, do so first.  This was designed to be a starting point of an
  * implementation.  This is not officially part of libpng, is hereby placed
  * in the public domain, and therefore does not require a copyright notice.
  *
@@ -26,16 +26,17 @@
  * see also the programs in the contrib directory.
  */
 
-/* The simple, but restricted, approach to reading a PNG file or data stream
- * just requires two function calls, as in the following complete program.
- * Writing a file just needs one function call, so long as the data has an
+/* The simple, but restricted approach to reading a PNG file or data stream
+ * requires just two function calls, as in the following complete program.
+ * Writing a file needs just one function call, so long as the data has an
  * appropriate layout.
  *
  * The following code reads PNG image data from a file and writes it, in a
- * potentially new format, to a new file.  While this code will compile there is
- * minimal (insufficient) error checking; for a more realistic version look at
- * contrib/examples/pngtopng.c
+ * potentially new format, to a new file.  While this code will compile, there
+ * is minimal (insufficient) error checking.  For a more realistic version,
+ * see contrib/examples/pngtopng.c
  */
+
 #include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
@@ -70,28 +71,28 @@
           */
          buffer = malloc(PNG_IMAGE_SIZE(image));
 
-         /* If enough memory was available read the image in the desired format
-          * then write the result out to the new file.  'background' is not
-          * necessary when reading the image because the alpha channel is
+         /* If enough memory was available, read the image in the desired
+          * format, then write the result out to the new file.  'background' is
+          * not necessary when reading the image, because the alpha channel is
           * preserved; if it were to be removed, for example if we requested
           * PNG_FORMAT_RGB, then either a solid background color would have to
-          * be supplied or the output buffer would have to be initialized to the
-          * actual background of the image.
+          * be supplied, or the output buffer would have to be initialized to
+          * the actual background of the image.
           *
           * The fourth argument to png_image_finish_read is the 'row_stride' -
           * this is the number of components allocated for the image in each
           * row.  It has to be at least as big as the value returned by
           * PNG_IMAGE_ROW_STRIDE, but if you just allocate space for the
-          * default, minimum, size using PNG_IMAGE_SIZE as above you can pass
+          * default, minimum size, using PNG_IMAGE_SIZE as above, you can pass
           * zero.
           *
           * The final argument is a pointer to a buffer for the colormap;
-          * colormaps have exactly the same format as a row of image pixels (so
-          * you choose what format to make the colormap by setting
+          * colormaps have exactly the same format as a row of image pixels
+          * (so you choose what format to make the colormap by setting
           * image.format).  A colormap is only returned if
           * PNG_FORMAT_FLAG_COLORMAP is also set in image.format, so in this
           * case NULL is passed as the final argument.  If you do want to force
-          * all images into an index/color-mapped format then you can use:
+          * all images into an index/color-mapped format, then you can use:
           *
           *    PNG_IMAGE_COLORMAP_SIZE(image)
           *
@@ -113,17 +114,15 @@
                exit(0);
             }
          }
-
          else
          {
             /* Calling png_image_free is optional unless the simplified API was
-             * not run to completion.  In this case if there wasn't enough
-             * memory for 'buffer' we didn't complete the read, so we must free
-             * the image:
+             * not run to completion.  In this case, if there wasn't enough
+             * memory for 'buffer', we didn't complete the read, so we must
+             * free the image:
              */
             if (buffer == NULL)
                png_image_free(&image);
-
             else
                free(buffer);
       }
@@ -132,65 +131,67 @@
        * textual message in the 'png_image' structure:
        */
       fprintf(stderr, "pngtopng: error: %s\n", image.message);
-      exit (1);
+      exit(1);
    }
 
    fprintf(stderr, "pngtopng: usage: pngtopng input-file output-file\n");
-   exit(1);
+   exit(2);
 }
 
 /* That's it ;-)  Of course you probably want to do more with PNG files than
  * just converting them all to 32-bit RGBA PNG files; you can do that between
  * the call to png_image_finish_read and png_image_write_to_file.  You can also
- * ask for the image data to be presented in a number of different formats.  You
- * do this by simply changing the 'format' parameter set before allocating the
- * buffer.
+ * ask for the image data to be presented in a number of different formats.
+ * You do this by simply changing the 'format' parameter set before allocating
+ * the buffer.
  *
  * The format parameter consists of five flags that define various aspects of
- * the image, you can simply add these together to get the format or you can use
- * one of the predefined macros from png.h (as above):
+ * the image.  You can simply add these together to get the format, or you can
+ * use one of the predefined macros from png.h (as above):
  *
- * PNG_FORMAT_FLAG_COLOR: if set the image will have three color components per
- *    pixel (red, green and blue), if not set the image will just have one
+ * PNG_FORMAT_FLAG_COLOR: if set, the image will have three color components
+ *    per pixel (red, green and blue); if not set, the image will just have one
  *    luminance (grayscale) component.
  *
- * PNG_FORMAT_FLAG_ALPHA: if set each pixel in the image will have an additional
- *    alpha value; a linear value that describes the degree the image pixel
- *    covers (overwrites) the contents of the existing pixel on the display.
+ * PNG_FORMAT_FLAG_ALPHA: if set, each pixel in the image will have an
+ *    additional alpha value; a linear value that describes the degree the
+ *    image pixel covers (overwrites) the contents of the existing pixel on the
+ *    display.
  *
- * PNG_FORMAT_FLAG_LINEAR: if set the components of each pixel will be returned
- *    as a series of 16-bit linear values, if not set the components will be
- *    returned as a series of 8-bit values encoded according to the 'sRGB'
- *    standard.  The 8-bit format is the normal format for images intended for
- *    direct display, because almost all display devices do the inverse of the
- *    sRGB transformation to the data they receive.  The 16-bit format is more
- *    common for scientific data and image data that must be further processed;
- *    because it is linear simple math can be done on the component values.
- *    Regardless of the setting of this flag the alpha channel is always linear,
- *    although it will be 8 bits or 16 bits wide as specified by the flag.
+ * PNG_FORMAT_FLAG_LINEAR: if set, the components of each pixel will be
+ *    returned as a series of 16-bit linear values; if not set, the components
+ *    will be returned as a series of 8-bit values encoded according to the
+ *    sRGB standard.  The 8-bit format is the normal format for images intended
+ *    for direct display, because almost all display devices do the inverse of
+ *    the sRGB transformation to the data they receive.  The 16-bit format is
+ *    more common for scientific data and image data that must be further
+ *    processed; because it is linear, simple math can be done on the component
+ *    values.  Regardless of the setting of this flag, the alpha channel is
+ *    always linear, although it will be 8 bits or 16 bits wide as specified by
+ *    the flag.
  *
- * PNG_FORMAT_FLAG_BGR: if set the components of a color pixel will be returned
- *    in the order blue, then green, then red.  If not set the pixel components
- *    are in the order red, then green, then blue.
+ * PNG_FORMAT_FLAG_BGR: if set, the components of a color pixel will be
+ *    returned in the order blue, then green, then red.  If not set, the pixel
+ *    components are in the order red, then green, then blue.
  *
- * PNG_FORMAT_FLAG_AFIRST: if set the alpha channel (if present) precedes the
- *    color or grayscale components.  If not set the alpha channel follows the
+ * PNG_FORMAT_FLAG_AFIRST: if set, the alpha channel (if present) precedes the
+ *    color or grayscale components.  If not set, the alpha channel follows the
  *    components.
  *
  * You do not have to read directly from a file.  You can read from memory or,
  * on systems that support it, from a <stdio.h> FILE*.  This is controlled by
- * the particular png_image_read_from_ function you call at the start.  Likewise
- * on write you can write to a FILE* if your system supports it.  Check the
- * macro PNG_STDIO_SUPPORTED to see if stdio support has been included in your
- * libpng build.
+ * the particular png_image_read_from_ function you call at the start.
+ * Likewise, on write, you can write to a FILE* if your system supports it.
+ * Check the macro PNG_STDIO_SUPPORTED to see if stdio support has been
+ * included in your libpng build.
  *
- * If you read 16-bit (PNG_FORMAT_FLAG_LINEAR) data you may need to write it in
- * the 8-bit format for display.  You do this by setting the convert_to_8bit
+ * If you read 16-bit (PNG_FORMAT_FLAG_LINEAR) data, you may need to write it
+ * in the 8-bit format for display.  You do this by setting the convert_to_8bit
  * flag to 'true'.
  *
  * Don't repeatedly convert between the 8-bit and 16-bit forms.  There is
- * significant data loss when 16-bit data is converted to the 8-bit encoding and
- * the current libpng implementation of conversion to 16-bit is also
+ * significant data loss when 16-bit data is converted to the 8-bit encoding,
+ * and the current libpng implementation of conversion to 16-bit is also
  * significantly lossy.  The latter will be fixed in the future, but the former
  * is unavoidable - the 8-bit format just doesn't have enough resolution.
  */
@@ -201,10 +202,10 @@
  * interfaces.
  *
  * All these interfaces require that you do your own error handling - your
- * program must be able to arrange for control to return to your own code any
- * time libpng encounters a problem.  There are several ways to do this, but the
- * standard way is to use the ANSI-C (C90) <setjmp.h> interface to establish a
- * return point within your own code.  You must do this if you do not use the
+ * program must be able to arrange for control to return to your own code, any
+ * time libpng encounters a problem.  There are several ways to do this, but
+ * the standard way is to use the <setjmp.h> interface to establish a return
+ * point within your own code.  You must do this if you do not use the
  * simplified interface (above).
  *
  * The first step is to include the header files you need, including the libpng
@@ -216,7 +217,7 @@
  /* The png_jmpbuf() macro, used in error handling, became available in
   * libpng version 1.0.6.  If you want to be able to run your code with older
   * versions of libpng, you must define the macro yourself (but only if it
-  * is not already defined by libpng!).
+  * is not already defined by libpng!)
   */
 
 #ifndef png_jmpbuf
@@ -224,10 +225,10 @@
 #endif
 
 /* Check to see if a file is a PNG file using png_sig_cmp().  png_sig_cmp()
- * returns zero if the image is a PNG and nonzero if it isn't a PNG.
+ * returns zero if the image is a PNG, and nonzero otherwise.
  *
  * The function check_if_png() shown here, but not used, returns nonzero (true)
- * if the file can be opened and is a PNG, 0 (false) otherwise.
+ * if the file can be opened and is a PNG, and 0 (false) otherwise.
  *
  * If this call is successful, and you are going to keep the file open,
  * you should call png_set_sig_bytes(png_ptr, PNG_BYTES_TO_CHECK); once
@@ -240,7 +241,7 @@
  *
  * Many applications already read the first 2 or 4 bytes from the start
  * of the image to determine the file type, so it would be easiest just
- * to pass the bytes to png_sig_cmp() or even skip that if you know
+ * to pass the bytes to png_sig_cmp(), or even skip that if you know
  * you have a PNG file, and call png_set_sig_bytes().
  */
 #define PNG_BYTES_TO_CHECK 4
@@ -252,13 +253,13 @@
    if ((*fp = fopen(file_name, "rb")) == NULL)
       return 0;
 
-   /* Read in some of the signature bytes */
+   /* Read in some of the signature bytes. */
    if (fread(buf, 1, PNG_BYTES_TO_CHECK, *fp) != PNG_BYTES_TO_CHECK)
       return 0;
 
    /* Compare the first PNG_BYTES_TO_CHECK bytes of the signature.
-      Return nonzero (true) if they match */
-
+    * Return nonzero (true) if they match.
+    */
    return(!png_sig_cmp(buf, 0, PNG_BYTES_TO_CHECK));
 }
 
@@ -269,7 +270,7 @@
  * some or all of the magic bytes read - see comments above).
  */
 #ifdef open_file /* prototype 1 */
-void read_png(char *file_name)  /* We need to open the file */
+void read_png(char *file_name) /* We need to open the file */
 {
    png_structp png_ptr;
    png_infop info_ptr;
@@ -282,7 +283,7 @@
       return (ERROR);
 
 #else no_open_file /* prototype 2 */
-void read_png(FILE *fp, int sig_read)  /* File is already open */
+void read_png(FILE *fp, int sig_read) /* File is already open */
 {
    png_structp png_ptr;
    png_infop info_ptr;
@@ -294,7 +295,7 @@
     * functions.  If you want to use the default stderr and longjump method,
     * you can supply NULL for the last three parameters.  We also supply the
     * the compiler header file version, so that we know if the application
-    * was compiled with a compatible version of the library.  REQUIRED
+    * was compiled with a compatible version of the library.  REQUIRED.
     */
    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
        png_voidp user_error_ptr, user_error_fn, user_warning_fn);
@@ -318,35 +319,33 @@
     * the normal method of doing things with libpng).  REQUIRED unless you
     * set up your own error handlers in the png_create_read_struct() earlier.
     */
-
    if (setjmp(png_jmpbuf(png_ptr)))
    {
-      /* Free all of the memory associated with the png_ptr and info_ptr */
+      /* Free all of the memory associated with the png_ptr and info_ptr. */
       png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
       fclose(fp);
-      /* If we get here, we had a problem reading the file */
+      /* If we get here, we had a problem reading the file. */
       return (ERROR);
    }
 
-   /* One of the following I/O initialization methods is REQUIRED */
+   /* One of the following I/O initialization methods is REQUIRED. */
 #ifdef streams /* PNG file I/O method 1 */
-   /* Set up the input control if you are using standard C streams */
+   /* Set up the input control if you are using standard C streams. */
    png_init_io(png_ptr, fp);
 
 #else no_streams /* PNG file I/O method 2 */
    /* If you are using replacement read functions, instead of calling
-    * png_init_io() here you would call:
+    * png_init_io(), you would call:
     */
    png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn);
-   /* where user_io_ptr is a structure you want available to the callbacks */
+   /* where user_io_ptr is a structure you want available to the callbacks. */
 #endif no_streams /* Use only one I/O method! */
 
    /* If we have already read some of the signature */
    png_set_sig_bytes(png_ptr, sig_read);
 
 #ifdef hilevel
-   /*
-    * If you have enough memory to read in the entire image at once,
+   /* If you have enough memory to read in the entire image at once,
     * and you need to specify only transforms that can be controlled
     * with one of the PNG_TRANSFORM_* bits (this presently excludes
     * quantizing, filling, setting background, and doing gamma
@@ -356,10 +355,10 @@
    png_read_png(png_ptr, info_ptr, png_transforms, NULL);
 
 #else
-   /* OK, you're doing it the hard way, with the lower-level functions */
+   /* OK, you're doing it the hard way, with the lower-level functions. */
 
    /* The call to png_read_info() gives us all of the information from the
-    * PNG file before the first IDAT (image data chunk).  REQUIRED
+    * PNG file before the first IDAT (image data chunk).  REQUIRED.
     */
    png_read_info(png_ptr, info_ptr);
 
@@ -387,20 +386,21 @@
     */
    png_set_strip_alpha(png_ptr);
 
-   /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
+   /* Extract multiple pixels with bit depths of 1, 2 or 4 from a single
     * byte into separate bytes (useful for paletted and grayscale images).
     */
    png_set_packing(png_ptr);
 
    /* Change the order of packed pixels to least significant bit first
-    * (not useful if you are using png_set_packing). */
+    * (not useful if you are using png_set_packing).
+    */
    png_set_packswap(png_ptr);
 
-   /* Expand paletted colors into true RGB triplets */
+   /* Expand paletted colors into true RGB triplets. */
    if (color_type == PNG_COLOR_TYPE_PALETTE)
       png_set_palette_to_rgb(png_ptr);
 
-   /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
+   /* Expand grayscale images to the full 8 bits from 1, 2 or 4 bits/pixel. */
    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
       png_set_expand_gray_1_2_4_to_8(png_ptr);
 
@@ -411,12 +411,11 @@
       png_set_tRNS_to_alpha(png_ptr);
 
    /* Set the background color to draw transparent and alpha images over.
-    * It is possible to set the red, green, and blue components directly
-    * for paletted images instead of supplying a palette index.  Note that
+    * It is possible to set the red, green and blue components directly
+    * for paletted images, instead of supplying a palette index.  Note that,
     * even if the PNG file supplies a background, you are not required to
     * use it - you should use the (solid) application background if it has one.
     */
-
    png_color_16 my_background, *image_background;
 
    if (png_get_bKGD(png_ptr, info_ptr, &image_background) != 0)
@@ -426,32 +425,29 @@
       png_set_background(png_ptr, &my_background,
           PNG_BACKGROUND_GAMMA_SCREEN, 0, 1.0);
 
-   /* Some suggestions as to how to get a screen gamma value
+   /* Some suggestions as to how to get a screen gamma value.
     *
     * Note that screen gamma is the display_exponent, which includes
-    * the CRT_exponent and any correction for viewing conditions
+    * the CRT_exponent and any correction for viewing conditions.
     */
    if (/* We have a user-defined screen gamma value */)
-   {
       screen_gamma = user-defined screen_gamma;
-   }
-   /* This is one way that applications share the same screen gamma value */
+   /* This is one way that applications share the same screen gamma value. */
    else if ((gamma_str = getenv("SCREEN_GAMMA")) != NULL)
-   {
       screen_gamma = atof(gamma_str);
-   }
    /* If we don't have another value */
    else
    {
-      screen_gamma = PNG_DEFAULT_sRGB;  /* A good guess for a PC monitor
-                                           in a dimly lit room */
-      screen_gamma = PNG_GAMMA_MAC_18 or 1.0; /* Good guesses for Mac systems */
+      screen_gamma = PNG_DEFAULT_sRGB; /* A good guess for a PC monitor
+                                          in a dimly lit room */
+      screen_gamma = PNG_GAMMA_MAC_18 or 1.0; /* Good guesses for Mac
+                                                 systems */
    }
 
    /* Tell libpng to handle the gamma conversion for you.  The final call
     * is a good guess for PC generated images, but it should be configurable
-    * by the user at run time by the user.  It is strongly suggested that
-    * your application support gamma correction.
+    * by the user at run time.  Gamma correction support in your application
+    * is strongly recommended.
     */
 
    int intent;
@@ -468,7 +464,7 @@
    }
 
 #ifdef PNG_READ_QUANTIZE_SUPPORTED
-   /* Quantize RGB files down to 8-bit palette or reduce palettes
+   /* Quantize RGB files down to 8-bit palette, or reduce palettes
     * to the number of colors available on your screen.
     */
    if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
@@ -476,29 +472,26 @@
       int num_palette;
       png_colorp palette;
 
-      /* This reduces the image to the application supplied palette */
+      /* This reduces the image to the application-supplied palette. */
       if (/* We have our own palette */)
       {
-         /* An array of colors to which the image should be quantized */
+         /* An array of colors to which the image should be quantized. */
          png_color std_color_cube[MAX_SCREEN_COLORS];
-
          png_set_quantize(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
              MAX_SCREEN_COLORS, NULL, 0);
       }
-      /* This reduces the image to the palette supplied in the file */
+      /* This reduces the image to the palette supplied in the file. */
       else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette) != 0)
       {
          png_uint_16p histogram = NULL;
-
          png_get_hIST(png_ptr, info_ptr, &histogram);
-
          png_set_quantize(png_ptr, palette, num_palette,
              max_screen_colors, histogram, 0);
       }
    }
 #endif /* READ_QUANTIZE */
 
-   /* Invert monochrome files to have 0 as white and 1 as black */
+   /* Invert monochrome files to have 0 as white and 1 as black. */
    png_set_invert_mono(png_ptr);
 
    /* If you want to shift the pixel values from the range [0,255] or
@@ -508,22 +501,21 @@
    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT) != 0)
    {
       png_color_8p sig_bit_p;
-
       png_get_sBIT(png_ptr, info_ptr, &sig_bit_p);
       png_set_shift(png_ptr, sig_bit_p);
    }
 
-   /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
+   /* Flip the RGB pixels to BGR (or RGBA to BGRA). */
    if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
       png_set_bgr(png_ptr);
 
-   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
+   /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR). */
    png_set_swap_alpha(png_ptr);
 
-   /* Swap bytes of 16-bit files to least significant byte first */
+   /* Swap bytes of 16-bit files to least significant byte first. */
    png_set_swap(png_ptr);
 
-   /* Add filler (or alpha) byte (before/after each RGB triplet) */
+   /* Add filler (or alpha) byte (before/after each RGB triplet). */
    png_set_filler(png_ptr, 0xffff, PNG_FILLER_AFTER);
 
 #ifdef PNG_READ_INTERLACING_SUPPORTED
@@ -536,40 +528,31 @@
    number_passes = 1;
 #endif /* READ_INTERLACING */
 
-
    /* Optional call to gamma correct and add the background to the palette
     * and update info structure.  REQUIRED if you are expecting libpng to
-    * update the palette for you (ie you selected such a transform above).
+    * update the palette for you (i.e. you selected such a transform above).
     */
    png_read_update_info(png_ptr, info_ptr);
 
    /* Allocate the memory to hold the image using the fields of info_ptr. */
-
-   /* The easiest way to read the image: */
    png_bytep row_pointers[height];
-
-   /* Clear the pointer array */
    for (row = 0; row < height; row++)
-      row_pointers[row] = NULL;
-
+      row_pointers[row] = NULL; /* Clear the pointer array */
    for (row = 0; row < height; row++)
       row_pointers[row] = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
           info_ptr));
 
-   /* Now it's time to read the image.  One of these methods is REQUIRED */
+   /* Now it's time to read the image.  One of these methods is REQUIRED. */
 #ifdef entire /* Read the entire image in one go */
    png_read_image(png_ptr, row_pointers);
 
 #else no_entire /* Read the image one or more scanlines at a time */
    /* The other way to read images - deal with interlacing: */
-
    for (pass = 0; pass < number_passes; pass++)
    {
 #ifdef single /* Read the image a single row at a time */
       for (y = 0; y < height; y++)
-      {
          png_read_rows(png_ptr, &row_pointers[y], NULL, 1);
-      }
 
 #else no_single /* Read the image several rows at a time */
       for (y = 0; y < height; y += number_of_rows)
@@ -583,24 +566,24 @@
 #endif no_sparkle /* Use only one of these two methods */
       }
 
-      /* If you want to display the image after every pass, do so here */
+      /* If you want to display the image after every pass, do so here. */
 #endif no_single /* Use only one of these two methods */
    }
 #endif no_entire /* Use only one of these two methods */
 
-   /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
+   /* Read rest of file, and get additional chunks in info_ptr.  REQUIRED. */
    png_read_end(png_ptr, info_ptr);
 #endif hilevel
 
-   /* At this point you have read the entire image */
+   /* At this point you have read the entire image. */
 
-   /* Clean up after the read, and free any memory allocated - REQUIRED */
+   /* Clean up after the read, and free any memory allocated.  REQUIRED. */
    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
 
-   /* Close the file */
+   /* Close the file. */
    fclose(fp);
 
-   /* That's it */
+   /* That's it! */
    return (OK);
 }
 
@@ -612,34 +595,30 @@
    /* Create and initialize the png_struct with the desired error handler
     * functions.  If you want to use the default stderr and longjump method,
     * you can supply NULL for the last three parameters.  We also check that
-    * the library version is compatible in case we are using dynamically
+    * the library version is compatible, in case we are using dynamically
     * linked libraries.
     */
    *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
         png_voidp user_error_ptr, user_error_fn, user_warning_fn);
-
    if (*png_ptr == NULL)
    {
       *info_ptr = NULL;
       return (ERROR);
    }
-
    *info_ptr = png_create_info_struct(png_ptr);
-
    if (*info_ptr == NULL)
    {
       png_destroy_read_struct(png_ptr, info_ptr, NULL);
       return (ERROR);
    }
-
    if (setjmp(png_jmpbuf((*png_ptr))))
    {
       png_destroy_read_struct(png_ptr, info_ptr, NULL);
       return (ERROR);
    }
 
-   /* This one's new.  You will need to provide all three
-    * function callbacks, even if you aren't using them all.
+   /* You will need to provide all three function callbacks,
+    * even if you aren't using all of them.
     * If you aren't using all functions, you can specify NULL
     * parameters.  Even when all three functions are NULL,
     * you need to call png_set_progressive_read_fn().
@@ -652,7 +631,6 @@
     */
    png_set_progressive_read_fn(*png_ptr, (void *)stream_data,
        info_callback, row_callback, end_callback);
-
    return (OK);
 }
 
@@ -662,18 +640,18 @@
 {
    if (setjmp(png_jmpbuf((*png_ptr))))
    {
-      /* Free the png_ptr and info_ptr memory on error */
+      /* Free the png_ptr and info_ptr memory on error. */
       png_destroy_read_struct(png_ptr, info_ptr, NULL);
       return (ERROR);
    }
 
-   /* This one's new also.  Simply give it chunks of data as
-    * they arrive from the data stream (in order, of course).
+   /* Give chunks of data as they arrive from the data stream
+    * (in order, of course).
     * On segmented machines, don't give it any more than 64K.
     * The library seems to run fine with sizes of 4K, although
-    * you can give it much less if necessary (I assume you can
+    * you can give it much less if necessary. (I assume you can
     * give it chunks of 1 byte, but I haven't tried with less
-    * than 256 bytes yet).  When this function returns, you may
+    * than 256 bytes yet.)  When this function returns, you may
     * want to display any rows that were generated in the row
     * callback, if you aren't already displaying them there.
     */
@@ -695,8 +673,7 @@
 row_callback(png_structp png_ptr, png_bytep new_row,
     png_uint_32 row_num, int pass)
 {
-   /*
-    * This function is called for every row in the image.  If the
+   /* This function is called for every row in the image.  If the
     * image is interlaced, and you turned on the interlace handler,
     * this function will be called for every row in every pass.
     *
@@ -707,25 +684,22 @@
     * The new row data pointer "new_row" may be NULL, indicating there is
     * no new data to be replaced (in cases of interlace loading).
     *
-    * If new_row is not NULL then you need to call
-    * png_progressive_combine_row() to replace the corresponding row as
+    * If new_row is not NULL, then you need to call
+    * png_progressive_combine_row(), to replace the corresponding row as
     * shown below:
     */
 
-   /* Get pointer to corresponding row in our
-    * PNG read buffer.
-    */
+   /* Get pointer to corresponding row in our PNG read buffer. */
    png_bytep old_row = ((png_bytep *)our_data)[row_num];
 
 #ifdef PNG_READ_INTERLACING_SUPPORTED
-   /* If both rows are allocated then copy the new row
+   /* If both rows are allocated, then copy the new row
     * data to the corresponding row data.
     */
-   if ((old_row != NULL) && (new_row != NULL))
-   png_progressive_combine_row(png_ptr, old_row, new_row);
+   if (old_row != NULL && new_row != NULL)
+      png_progressive_combine_row(png_ptr, old_row, new_row);
 
-   /*
-    * The rows and passes are called in order, so you don't really
+   /* The rows and passes are called in order, so you don't really
     * need the row_num and pass, but I'm supplying them because it
     * may make your life easier.
     *
@@ -736,7 +710,6 @@
     * (it just does the memcpy for you) if it will make the code
     * easier.  Thus, you can just do this for all cases:
     */
-
    png_progressive_combine_row(png_ptr, old_row, new_row);
 
    /* where old_row is what was displayed for previous rows.  Note
@@ -783,14 +756,13 @@
     */
    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
        png_voidp user_error_ptr, user_error_fn, user_warning_fn);
-
    if (png_ptr == NULL)
    {
       fclose(fp);
       return (ERROR);
    }
 
-   /* Allocate/initialize the image information data.  REQUIRED */
+   /* Allocate/initialize the image information data.  REQUIRED. */
    info_ptr = png_create_info_struct(png_ptr);
    if (info_ptr == NULL)
    {
@@ -799,30 +771,30 @@
       return (ERROR);
    }
 
-   /* Set error handling.  REQUIRED if you aren't supplying your own
+   /* Set up error handling.  REQUIRED if you aren't supplying your own
     * error handling functions in the png_create_write_struct() call.
     */
    if (setjmp(png_jmpbuf(png_ptr)))
    {
-      /* If we get here, we had a problem writing the file */
+      /* If we get here, we had a problem writing the file. */
       fclose(fp);
       png_destroy_write_struct(&png_ptr, &info_ptr);
       return (ERROR);
    }
 
-   /* One of the following I/O initialization functions is REQUIRED */
+   /* One of the following I/O initialization functions is REQUIRED. */
 
 #ifdef streams /* I/O initialization method 1 */
-   /* Set up the output control if you are using standard C streams */
+   /* Set up the output control if you are using standard C streams. */
    png_init_io(png_ptr, fp);
 
 #else no_streams /* I/O initialization method 2 */
    /* If you are using replacement write functions, instead of calling
-    * png_init_io() here you would call
+    * png_init_io(), you would call:
     */
    png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn,
        user_IO_flush_function);
-   /* where user_io_ptr is a structure you want available to the callbacks */
+   /* where user_io_ptr is a structure you want available to the callbacks. */
 #endif no_streams /* Only use one initialization method */
 
 #ifdef hilevel
@@ -833,30 +805,32 @@
    png_write_png(png_ptr, info_ptr, png_transforms, NULL);
 
 #else
-   /* This is the hard way */
+   /* This is the hard way. */
 
    /* Set the image information here.  Width and height are up to 2^31,
-    * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on
-    * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY,
+    * bit_depth is one of 1, 2, 4, 8 or 16, but valid values also depend on
+    * the color_type selected.  color_type is one of PNG_COLOR_TYPE_GRAY,
     * PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE, PNG_COLOR_TYPE_RGB,
     * or PNG_COLOR_TYPE_RGB_ALPHA.  interlace is either PNG_INTERLACE_NONE or
     * PNG_INTERLACE_ADAM7, and the compression_type and filter_type MUST
-    * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE. REQUIRED
+    * currently be PNG_COMPRESSION_TYPE_BASE and PNG_FILTER_TYPE_BASE.
+    * REQUIRED.
     */
-   png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth, PNG_COLOR_TYPE_???,
-       PNG_INTERLACE_????, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+   png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
+       PNG_COLOR_TYPE_???, PNG_INTERLACE_????,
+       PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 
-   /* Set the palette if there is one.  REQUIRED for indexed-color images */
-   palette = (png_colorp)png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH
-             * (sizeof (png_color)));
+   /* Set the palette if there is one.  REQUIRED for indexed-color images. */
+   palette = (png_colorp)png_malloc(png_ptr,
+       PNG_MAX_PALETTE_LENGTH * (sizeof (png_color)));
    /* ... Set palette colors ... */
    png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH);
-   /* You must not free palette here, because png_set_PLTE only makes a link to
-    * the palette that you malloced.  Wait until you are about to destroy
+   /* You must not free palette here, because png_set_PLTE only makes a link
+    * to the palette that you allocated.  Wait until you are about to destroy
     * the png structure.
     */
 
-   /* Optional significant bit (sBIT) chunk */
+   /* Optional significant bit (sBIT) chunk. */
    png_color_8 sig_bit;
 
    /* If we are dealing with a grayscale image then */
@@ -872,18 +846,17 @@
 
    png_set_sBIT(png_ptr, info_ptr, &sig_bit);
 
-
    /* Optional gamma chunk is strongly suggested if you have any guess
     * as to the correct gamma of the image.
     */
    png_set_gAMA(png_ptr, info_ptr, gamma);
 
-   /* Optionally write comments into the image */
+   /* Optionally write comments into the image. */
    {
       png_text text_ptr[3];
 
-      char key0[]="Title";
-      char text0[]="Mona Lisa";
+      char key0[] = "Title";
+      char text0[] = "Mona Lisa";
       text_ptr[0].key = key0;
       text_ptr[0].text = text0;
       text_ptr[0].compression = PNG_TEXT_COMPRESSION_NONE;
@@ -891,8 +864,8 @@
       text_ptr[0].lang = NULL;
       text_ptr[0].lang_key = NULL;
 
-      char key1[]="Author";
-      char text1[]="Leonardo DaVinci";
+      char key1[] = "Author";
+      char text1[] = "Leonardo DaVinci";
       text_ptr[1].key = key1;
       text_ptr[1].text = text1;
       text_ptr[1].compression = PNG_TEXT_COMPRESSION_NONE;
@@ -900,8 +873,8 @@
       text_ptr[1].lang = NULL;
       text_ptr[1].lang_key = NULL;
 
-      char key2[]="Description";
-      char text2[]="<long text>";
+      char key2[] = "Description";
+      char text2[] = "<long text>";
       text_ptr[2].key = key2;
       text_ptr[2].text = text2;
       text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
@@ -912,14 +885,14 @@
       png_set_text(write_ptr, write_info_ptr, text_ptr, 3);
    }
 
-   /* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs */
+   /* Other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs. */
 
-   /* Note that if sRGB is present the gAMA and cHRM chunks must be ignored
+   /* Note that if sRGB is present, the gAMA and cHRM chunks must be ignored
     * on read and, if your application chooses to write them, they must
-    * be written in accordance with the sRGB profile
+    * be written in accordance with the sRGB profile.
     */
 
-   /* Write the file header information.  REQUIRED */
+   /* Write the file header information.  REQUIRED. */
    png_write_info(png_ptr, info_ptr);
 
    /* If you want, you can write the info in two steps, in case you need to
@@ -943,7 +916,7 @@
     * all optional.  Only call them if you want them.
     */
 
-   /* Invert monochrome pixels */
+   /* Invert monochrome pixels. */
    png_set_invert_mono(png_ptr);
 
    /* Shift the pixels up to a legal bit depth and fill in
@@ -951,30 +924,29 @@
     */
    png_set_shift(png_ptr, &sig_bit);
 
-   /* Pack pixels into bytes */
+   /* Pack pixels into bytes. */
    png_set_packing(png_ptr);
 
-   /* Swap location of alpha bytes from ARGB to RGBA */
+   /* Swap location of alpha bytes from ARGB to RGBA. */
    png_set_swap_alpha(png_ptr);
 
    /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into
-    * RGB (4 channels -> 3 channels). The second parameter is not used.
+    * RGB (4 channels -> 3 channels).  The second parameter is not used.
     */
    png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
 
-   /* Flip BGR pixels to RGB */
+   /* Flip BGR pixels to RGB. */
    png_set_bgr(png_ptr);
 
-   /* Swap bytes of 16-bit files to most significant byte first */
+   /* Swap bytes of 16-bit files to most significant byte first. */
    png_set_swap(png_ptr);
 
-   /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats */
+   /* Swap bits of 1-bit, 2-bit, 4-bit packed pixel formats. */
    png_set_packswap(png_ptr);
 
-   /* Turn on interlace handling if you are not using png_write_image() */
+   /* Turn on interlace handling if you are not using png_write_image(). */
    if (interlacing != 0)
       number_passes = png_set_interlace_handling(png_ptr);
-
    else
       number_passes = 1;
 
@@ -984,29 +956,28 @@
     */
    png_uint_32 k, height, width;
 
-   /* In this example, "image" is a one-dimensional array of bytes */
+   /* In this example, "image" is a one-dimensional array of bytes. */
 
-   /* Guard against integer overflow */
-   if (height > PNG_SIZE_MAX/(width*bytes_per_pixel)) {
-      png_error(png_ptr, "Image_data buffer would be too large");
-   }
-   png_byte image[height*width*bytes_per_pixel];
+   /* Guard against integer overflow. */
+   if (height > PNG_SIZE_MAX / (width * bytes_per_pixel))
+      png_error(png_ptr, "Image data buffer would be too large");
 
+   png_byte image[height * width * bytes_per_pixel];
    png_bytep row_pointers[height];
 
-   if (height > PNG_UINT_32_MAX/(sizeof (png_bytep)))
-      png_error (png_ptr, "Image is too tall to process in memory");
+   if (height > PNG_UINT_32_MAX / (sizeof (png_bytep)))
+      png_error(png_ptr, "Image is too tall to process in memory");
 
-   /* Set up pointers into your "image" byte array */
+   /* Set up pointers into your "image" byte array. */
    for (k = 0; k < height; k++)
-      row_pointers[k] = image + k*width*bytes_per_pixel;
+      row_pointers[k] = image + k * width * bytes_per_pixel;
 
-   /* One of the following output methods is REQUIRED */
+   /* One of the following output methods is REQUIRED. */
 
 #ifdef entire /* Write out the entire image data in one call */
    png_write_image(png_ptr, row_pointers);
 
-   /* The other way to write the image - deal with interlacing */
+   /* The other way to write the image - deal with interlacing. */
 
 #else no_entire /* Write out the image data by one or more scanlines */
 
@@ -1018,27 +989,27 @@
       /* Write a few rows at a time. */
       png_write_rows(png_ptr, &row_pointers[first_row], number_of_rows);
 
-      /* If you are only writing one row at a time, this works */
+      /* If you are only writing one row at a time, this works. */
       for (y = 0; y < height; y++)
          png_write_rows(png_ptr, &row_pointers[y], 1);
    }
 #endif no_entire /* Use only one output method */
 
    /* You can write optional chunks like tEXt, zTXt, and tIME at the end
-    * as well.  Shouldn't be necessary in 1.2.0 and up as all the public
-    * chunks are supported and you can use png_set_unknown_chunks() to
+    * as well.  Shouldn't be necessary in 1.2.0 and up, as all the public
+    * chunks are supported, and you can use png_set_unknown_chunks() to
     * register unknown chunks into the info structure to be written out.
     */
 
-   /* It is REQUIRED to call this to finish writing the rest of the file */
+   /* It is REQUIRED to call this to finish writing the rest of the file. */
    png_write_end(png_ptr, info_ptr);
 #endif hilevel
 
-   /* If you png_malloced a palette, free it here (don't free info_ptr->palette,
-    * as recommended in versions 1.0.5m and earlier of this example; if
-    * libpng mallocs info_ptr->palette, libpng will free it).  If you
-    * allocated it with malloc() instead of png_malloc(), use free() instead
-    * of png_free().
+   /* If you png_malloced a palette, free it here.
+    * (Don't free info_ptr->palette, as shown in versions 1.0.5m and earlier of
+    * this example; if libpng mallocs info_ptr->palette, libpng will free it).
+    * If you allocated it with malloc() instead of png_malloc(), use free()
+    * instead of png_free().
     */
    png_free(png_ptr, palette);
    palette = NULL;
@@ -1049,19 +1020,20 @@
     */
    png_free(png_ptr, trans);
    trans = NULL;
-   /* Whenever you use png_free() it is a good idea to set the pointer to
+
+   /* Whenever you use png_free(), it is a good idea to set the pointer to
     * NULL in case your application inadvertently tries to png_free() it
-    * again.  When png_free() sees a NULL it returns without action, thus
-    * avoiding the double-free security problem.
+    * again.  When png_free() sees a NULL it returns without action, avoiding
+    * the double-free problem.
     */
 
-   /* Clean up after the write, and free any memory allocated */
+   /* Clean up after the write, and free any allocated memory. */
    png_destroy_write_struct(&png_ptr, &info_ptr);
 
-   /* Close the file */
+   /* Close the file. */
    fclose(fp);
 
-   /* That's it */
+   /* That's it! */
    return (OK);
 }
 
diff --git a/png.c b/png.c
index a15df02..7ba7f64 100644
--- a/png.c
+++ b/png.c
@@ -3128,11 +3128,11 @@
             /* The total output count (max) is now 4+precision */
 
             /* Check for an exponent, if we don't need one we are
-             * done and just need to terminate the string.  At
-             * this point exp_b10==(-1) is effectively a flag - it got
-             * to '-1' because of the decrement after outputting
-             * the decimal point above (the exponent required is
-             * *not* -1!)
+             * done and just need to terminate the string.  At this
+             * point, exp_b10==(-1) is effectively a flag: it got
+             * to '-1' because of the decrement, after outputting
+             * the decimal point above. (The exponent required is
+             * *not* -1.)
              */
             if (exp_b10 >= (-1) && exp_b10 <= 2)
             {
@@ -3978,10 +3978,10 @@
    /* CSE the division and work round wacky GCC warnings (see the comments
     * in png_gamma_8bit_correct for where these come from.)
     */
-   const double fmax = 1./(((png_int_32)1 << (16U - shift))-1);
+   double fmax = 1.0 / (((png_int_32)1 << (16U - shift)) - 1);
 #endif
-   unsigned int max = (1U << (16U - shift))-1U;
-   unsigned int max_by_2 = 1U << (15U-shift);
+   unsigned int max = (1U << (16U - shift)) - 1U;
+   unsigned int max_by_2 = 1U << (15U - shift);
    unsigned int i;
 
    png_uint_16pp table = *ptable =
diff --git a/pngconf.h b/pngconf.h
index 40e8ee0..3a05b89 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -63,8 +63,8 @@
  */
 #define PNG_CONST const /* backward compatibility only */
 
-/* This controls optimization of the reading of 16-bit and 32-bit values
- * from PNG files.  It can be set on a per-app-file basis - it
+/* This controls optimization of the reading of 16-bit and 32-bit
+ * values from PNG files.  It can be set on a per-app-file basis: it
  * just changes whether a macro is used when the function is called.
  * The library builder sets the default; if read functions are not
  * built into the library the macro implementation is forced on.
diff --git a/scripts/descrip.mms b/scripts/descrip.mms
index 463c425..a3aefbf 100644
--- a/scripts/descrip.mms
+++ b/scripts/descrip.mms
@@ -16,10 +16,10 @@
 CFLAGS= $(C_DEB) $(CC_DEFS) $(PREF)
 
 all : pngtest.exe libpng.olb
-		@ write sys$output " pngtest available"
+	@ write sys$output " pngtest available"
 
 libpng.olb : libpng.olb($(OBJS))
-	@ write sys$output " Libpng available"
+	@ write sys$output " libpng available"
 
 
 pngtest.exe : pngtest.obj libpng.olb
diff --git a/scripts/makefile.hp64 b/scripts/makefile.hp64
index cde0d15..4421e78 100644
--- a/scripts/makefile.hp64
+++ b/scripts/makefile.hp64
@@ -1,7 +1,7 @@
 # makefile for libpng, HPUX (10.20 and 11.00) using the ANSI/C product.
 # Copyright (C) 1999-2002, 2006, 2009, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42
-# contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
+# Contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
 #
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
diff --git a/scripts/makefile.hpux b/scripts/makefile.hpux
index 4489757..27b312a 100644
--- a/scripts/makefile.hpux
+++ b/scripts/makefile.hpux
@@ -1,7 +1,7 @@
 # makefile for libpng, HPUX (10.20 and 11.00) using the ANSI/C product.
 # Copyright (C) 1999-2002, 2006, 2010-2014 Glenn Randers-Pehrson
 # Copyright (C) 1995 Guy Eric Schalnat, Group 42
-# contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
+# Contributed by Jim Rice and updated by Chris Schleicher, Hewlett Packard
 #
 # This code is released under the libpng license.
 # For conditions of distribution and use, see the disclaimer
diff --git a/scripts/makefile.std b/scripts/makefile.std
index 30ab467..2f4871d 100644
--- a/scripts/makefile.std
+++ b/scripts/makefile.std
@@ -122,6 +122,7 @@
 pngmem.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 pngset.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 pngget.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
+pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 pngread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 pngrtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 pngrutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
@@ -129,6 +130,5 @@
 pngwrite.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 pngwtran.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 pngwutil.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
-pngpread.o: png.h pngconf.h pnglibconf.h pngpriv.h pngstruct.h pnginfo.h pngdebug.h
 
 pngtest.o: png.h pngconf.h pnglibconf.h
diff --git a/scripts/pnglibconf.dfa b/scripts/pnglibconf.dfa
index b298a72..15bd08e 100644
--- a/scripts/pnglibconf.dfa
+++ b/scripts/pnglibconf.dfa
@@ -8,7 +8,8 @@
 com
 version
 com
-com Copyright (c) 1998-2017 Glenn Randers-Pehrson
+com Copyright (c) 2018 Cosmin Truta
+com Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
 com
 com This code is released under the libpng license.
 com For conditions of distribution and use, see the disclaimer
diff --git a/scripts/pnglibconf.h.prebuilt b/scripts/pnglibconf.h.prebuilt
index 603a8cb..622f7cd 100644
--- a/scripts/pnglibconf.h.prebuilt
+++ b/scripts/pnglibconf.h.prebuilt
@@ -2,10 +2,10 @@
 
 /* pnglibconf.h - library build configuration */
 
-/* Libpng version 1.6.36.git */
+/* libpng version 1.6.36.git */
 
 /* Copyright (c) 2018 Cosmin Truta */
-/* Copyright (c) 1998-2018 Glenn Randers-Pehrson */
+/* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson */
 
 /* This code is released under the libpng license. */
 /* For conditions of distribution and use, see the disclaimer */
@@ -21,8 +21,6 @@
 #define PNG_ALIGNED_MEMORY_SUPPORTED
 /*#undef PNG_ARM_NEON_API_SUPPORTED*/
 /*#undef PNG_ARM_NEON_CHECK_SUPPORTED*/
-/*#undef PNG_POWERPC_VSX_API_SUPPORTED*/
-/*#undef PNG_POWERPC_VSX_CHECK_SUPPORTED*/
 #define PNG_BENIGN_ERRORS_SUPPORTED
 #define PNG_BENIGN_READ_ERRORS_SUPPORTED
 /*#undef PNG_BENIGN_WRITE_ERRORS_SUPPORTED*/
@@ -47,6 +45,8 @@
 #define PNG_IO_STATE_SUPPORTED
 #define PNG_MNG_FEATURES_SUPPORTED
 #define PNG_POINTER_INDEXING_SUPPORTED
+/*#undef PNG_POWERPC_VSX_API_SUPPORTED*/
+/*#undef PNG_POWERPC_VSX_CHECK_SUPPORTED*/
 #define PNG_PROGRESSIVE_READ_SUPPORTED
 #define PNG_READ_16BIT_SUPPORTED
 #define PNG_READ_ALPHA_MODE_SUPPORTED