diff -up freewrl-3.0.0-20170208git621ae4e/src/lib/display.c.checkdef freewrl-3.0.0-20170208git621ae4e/src/lib/display.c
--- freewrl-3.0.0-20170208git621ae4e/src/lib/display.c.checkdef	2017-02-08 10:58:51.948970415 -0500
+++ freewrl-3.0.0-20170208git621ae4e/src/lib/display.c	2017-02-08 10:59:50.875685580 -0500
@@ -182,7 +182,7 @@ void fv_swapbuffers(freewrl_params_t *d)
 void fv_change_GLcontext(freewrl_params_t* d){
 	//stub for non-desktop configs (they can't do multiple windows anyway)
 }
-#elif _MSC_VER
+#elif defined(_MSC_VER)
 //win32 in fwWindow32.c
 #elif __linux__  //LINUX
 //void fv_change_GLcontext(freewrl_params_t* d){