diff --git a/gfx/gl_common.h b/gfx/gl_common.h
index d12c244..b49e1c2 100644
--- a/gfx/gl_common.h
+++ b/gfx/gl_common.h
@@ -54,3 +54,4 @@ typedef char GLchar;
 #define glRenderbufferStorageEXT glRenderbufferStorage
 #define glDeleteRenderbuffersEXT glDeleteRenderbuffers
 
+static void (*glInvalidateFramebuffer)(GLenum target, GLsizei numAttachments, const GLenum* attachments) = 0;