diff --git a/src/gl-fun.h b/src/gl-fun.h
index a9862da..7d5d96e 100644
--- a/src/gl-fun.h
+++ b/src/gl-fun.h
@@ -114,6 +114,9 @@ typedef void (APIENTRYP _PFNGLBINDVERTEXARRAYPROC) (GLuint array);
 #define GL_NUM_EXTENSIONS 0x821D
 #define GL_READ_FRAMEBUFFER 0x8CA8
 #define GL_DRAW_FRAMEBUFFER 0x8CA9
+#define GL_UNPACK_ROW_LENGTH 0x0CF2
+#define GL_UNPACK_SKIP_PIXELS 0x0CF4
+#define GL_UNPACK_SKIP_ROWS 0x0CF3
 #endif
 
 #define GL_20_FUN \