diff --git a/src/win32/win32gliface.cpp b/src/win32/win32gliface.cpp
index 430e0d489..bb4368c2b 100644
--- a/src/win32/win32gliface.cpp
+++ b/src/win32/win32gliface.cpp
@@ -66,7 +66,7 @@ extern HWND			Window;
 extern BOOL AppActive;
 
 extern "C" {
-    _declspec(dllexport) DWORD NvOptimusEnablement = 0x00000001;
+    __declspec(dllexport) DWORD NvOptimusEnablement = 0x00000001;
     __declspec(dllexport) int AmdPowerXpressRequestHighPerformance = 1;	
 }