diff --git a/gfx/context/wgl_ctx.c b/gfx/context/wgl_ctx.c
index 5b0e77e401..106d4367bc 100644
--- a/gfx/context/wgl_ctx.c
+++ b/gfx/context/wgl_ctx.c
@@ -16,6 +16,11 @@
 
 // Win32/WGL context.
 
+// necessary for mingw32 multimon defines:
+#ifndef _WIN32_WINNT
+#define _WIN32_WINNT 0x0500 //_WIN32_WINNT_WIN2K
+#endif
+
 #include "../../driver.h"
 #include "../gfx_context.h"
 #include "../gl_common.h"