[libpng16] Fixed some bugs in ICC profile writing. The code should now accept

all potentially valid ICC profiles and reject obviously invalid ones.
It now uses png_error() to do so rather than casually writing a PNG
without the necessary color data.
diff --git a/pngpriv.h b/pngpriv.h
index 9062367..56a545f 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -898,7 +898,7 @@
 #ifdef PNG_WRITE_iCCP_SUPPORTED
 PNG_INTERNAL_FUNCTION(void,png_write_iCCP,(png_structrp png_ptr,
     png_const_charp name, int compression_type,
-    png_const_charp profile, int proflen),PNG_EMPTY);
+    png_const_bytep profile, png_uint_32 proflen),PNG_EMPTY);
    /* Note to maintainer: profile should be png_bytep */
 #endif