Imported from libpng-1.2.19beta21.tar

pngtest.c

@@ -1553,4 +1553,4 @@ main(int argc, char *argv[])
 }
 
 /* Generate a compiler error if there is an old png.h in the search path. */
-typedef version_1_2_19beta20 your_png_h_is_not_version_1_2_19beta20;
+typedef version_1_2_19beta21 your_png_h_is_not_version_1_2_19beta21;