diff -ruN a/ext/gd/gd.c b/ext/gd/gd.c
--- a/ext/gd/gd.c	2021-09-21 20:23:13.000000000 +0900
+++ b/ext/gd/gd.c	2021-09-25 12:14:22.927843511 +0900
@@ -97,6 +97,11 @@
 
 #include "gd_ctx.c"
 
+/* don't used libgd constants, not used, so going to be removed */
+#define PHP_GD_FLIP_HORIZONTAL 1
+#define PHP_GD_FLIP_VERTICAL   2
+#define PHP_GD_FLIP_BOTH       3
+
 /* as it is not really public, duplicate declaration here to avoid
    pointless warnings */
 int overflow2(int a, int b);
@@ -1137,9 +1142,9 @@
     /* GD2 image format types */
 	REGISTER_LONG_CONSTANT("IMG_GD2_RAW", GD2_FMT_RAW, CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("IMG_GD2_COMPRESSED", GD2_FMT_COMPRESSED, CONST_CS | CONST_PERSISTENT);
-	REGISTER_LONG_CONSTANT("IMG_FLIP_HORIZONTAL", GD_FLIP_HORINZONTAL, CONST_CS | CONST_PERSISTENT);
-	REGISTER_LONG_CONSTANT("IMG_FLIP_VERTICAL", GD_FLIP_VERTICAL, CONST_CS | CONST_PERSISTENT);
-	REGISTER_LONG_CONSTANT("IMG_FLIP_BOTH", GD_FLIP_BOTH, CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("IMG_FLIP_HORIZONTAL", PHP_GD_FLIP_HORIZONTAL, CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("IMG_FLIP_VERTICAL", PHP_GD_FLIP_VERTICAL, CONST_CS | CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("IMG_FLIP_BOTH", PHP_GD_FLIP_BOTH, CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("IMG_EFFECT_REPLACE", gdEffectReplace, CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("IMG_EFFECT_ALPHABLEND", gdEffectAlphaBlend, CONST_CS | CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("IMG_EFFECT_NORMAL", gdEffectNormal, CONST_CS | CONST_PERSISTENT);
@@ -4696,15 +4701,15 @@
 	}
 
 	switch (mode) {
-		case GD_FLIP_VERTICAL:
+		case PHP_GD_FLIP_VERTICAL:
 			gdImageFlipVertical(im);
 			break;
 
-		case GD_FLIP_HORINZONTAL:
+		case PHP_GD_FLIP_HORIZONTAL:
 			gdImageFlipHorizontal(im);
 			break;
 
-		case GD_FLIP_BOTH:
+		case PHP_GD_FLIP_BOTH:
 			gdImageFlipBoth(im);
 			break;