Fixed Bug #66901 php-gd 'c_color' NULL pointer dereference

Upstream https://bitbucket.org/libgd/gd-libgd/commits/463c3bd09bfe8e924e19acad7a2a6af16953a704

Notice: this fix don't manage monochrome/monovisual values
but just fix the security issue CVE-2014-2497
failing when trying to load such an image

Author: remicollet

ext/gd/libgd/gdxpm.c

@@ -31,12 +31,17 @@ gdImagePtr gdImageCreateFromXpm (char *filename)
 	if (ret != XpmSuccess) {
 		return 0;
 	}
+	number = image.ncolors;
+	for(i = 0; i < number; i++) {
+		if (!image.colorTable[i].c_color) {
+			goto done;
+		}
+	}
 
 	if (!(im = gdImageCreate(image.width, image.height))) {
 		goto done;
 	}
 
-	number = image.ncolors;
 	colors = (int *) safe_emalloc(number, sizeof(int), 0);
 	for (i = 0; i < number; i++) {
 		switch (strlen (image.colorTable[i].c_color)) {