[master] Imported from libpng-1.6.30.tar

pngtest.c

@@ -2088,4 +2088,4 @@ main(void)
 #endif
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef png_libpng_version_1_6_29 Your_png_h_is_not_version_1_6_29;
+typedef png_libpng_version_1_6_30 Your_png_h_is_not_version_1_6_30;