MFH: Allow compilation with gdlib 1.8

diff --git a/ext/gd/gd.c b/ext/gd/gd.c
index 2a9890968ce405e5b07a3916fd591b6379addf3e..046e08451ab703cb8d408ee0facbcf55c87fe362 100644 (file)
--- a/ext/gd/gd.c
+++ b/ext/gd/gd.c
@@ -3639,9 +3639,11 @@ static void _php_image_bw_convert( gdImagePtr im_org, gdIOCtx *out, int threshol
                return;
        }
 
+#ifdef HAVE_LIBGD20
        if (im_org->trueColor) {
                gdImageTrueColorToPalette(im_org, 1, 256);
        }
+#endif
 
        for (y = 0; y < dest_height; y++) {
                for (x = 0; x < dest_width; x++) {