diff --git a/reactos/lib/mesa32/src/drivers/windows/gdi/wmesadef.h b/reactos/lib/mesa32/src/drivers/windows/gdi/wmesadef.h
index b75123eaca4..d43e990ed3c 100644
--- a/reactos/lib/mesa32/src/drivers/windows/gdi/wmesadef.h
+++ b/reactos/lib/mesa32/src/drivers/windows/gdi/wmesadef.h
@@ -93,6 +93,7 @@ typedef struct _dibSection{
 }WMDIBSECTION, *PWMDIBSECTION;
 
 #ifdef COMPILE_SETPIXEL
+struct wmesa_context;
 typedef void (*SETPIXELTYPE)(struct wmesa_context *pwc, int iScanLine, int iPixel, BYTE r, BYTE g, BYTE b);
 #endif