fixed include checks for libpng under win

Author: weltling

ext/gd/config.w32

@@ -9,7 +9,8 @@ if (PHP_GD != "no") {
 		CHECK_LIB("freetype_a.lib;freetype.lib", "gd", PHP_GD) &&
 		CHECK_LIB("libpng_a.lib;libpng.lib", "gd", PHP_GD) &&
 		CHECK_HEADER_ADD_INCLUDE("gd.h", "CFLAGS_GD", PHP_GD + ";ext\\gd\\libgd") &&
-		CHECK_HEADER_ADD_INCLUDE("png.h", "CFLAGS_GD", PHP_GD +  ";" + PHP_PHP_BUILD + "\\include\\libpng12") &&
+		(CHECK_HEADER_ADD_INCLUDE("png.h", "CFLAGS_GD", PHP_GD +  ";" + PHP_PHP_BUILD + "\\include\\libpng") ||
+		CHECK_HEADER_ADD_INCLUDE("png.h", "CFLAGS_GD", PHP_GD +  ";" + PHP_PHP_BUILD + "\\include\\libpng12")) &&
 		(CHECK_LIB("libiconv_a.lib;libiconv.lib", "gd", PHP_GD) || CHECK_LIB("iconv_a.lib;iconv.lib", "gd", PHP_GD)) &&
 		 CHECK_HEADER_ADD_INCLUDE("iconv.h", "CFLAGS_GD", PHP_GD) && 
 		(((PHP_ZLIB=="no") && (CHECK_LIB("zlib_a.lib;zlib.lib", "gd", PHP_GD) )) ||