[libpng16] Removed need for -Wno-cast-align with clang. clang correctly warns
on alignment increasing pointer casts when -Wcast-align is passed. This
fixes the cases clang warns about either (pngread.c) by eliminating the
casts from png_bytep to png_uint_16p or, for pngrutil.c where the cast
is previously verified or pngstest.c where it is OK by introducing new
png_aligncast macros to do the cast in a way that clang accepts.
diff --git a/pngpriv.h b/pngpriv.h
index 8ec7dce..e09a10e 100644
--- a/pngpriv.h
+++ b/pngpriv.h
@@ -312,9 +312,15 @@
#ifdef __cplusplus
# define png_voidcast(type, value) static_cast<type>(value)
# define png_constcast(type, value) const_cast<type>(value)
+# define png_aligncast(type, value) \
+ static_cast<type>(static_cast<void*>(value))
+# define png_aligncastconst(type, value) \
+ static_cast<type>(static_cast<const void*>(value))
#else
# define png_voidcast(type, value) (value)
# define png_constcast(type, value) ((type)(value))
+# define png_aligncast(type, value) ((void*)(value))
+# define png_aligncastconst(type, value) ((const void*)(value))
#endif /* __cplusplus */
/* Some fixed point APIs are still required even if not exported because
