Windows OSMesa DLL only exports OSMesa functions....

third_party/glew/src/glew.c

 /*
 ** The OpenGL Extension Wrangler Library
 ** Copyright (C) 2002-2008, Milan Ikits <milan ikits[]ieee org>
 ** Copyright (C) 2002-2008, Marcelo E. Magallon <mmagallo[]debian org>
 ** Copyright (C) 2002, Lev Povalahev
 ** All rights reserved.
 ** 
 ** Redistribution and use in source and binary forms, with or without 
 ** modification, are permitted provided that the following conditions are met:
 ** 
@@ skipping 68 matching lines @@
   static HMODULE oglImage = NULL;
   static PFNOSMESAGETPROCADDRESSPROC osmesaGetProcAddress = NULL;
   void* proc = NULL;
 
   if (NULL == oglImage) {
     oglImage = LoadLibraryA("osmesa.dll");
     if (NULL == oglImage) {
       oglImage = LoadLibraryA("opengl32.dll");
     }
     else {
-      osmesaGetProcAddress = (PFNOSMESAGETPROCADDRESSPROC) GetProcAddress(oglImage, "_OSMesaGetProcAddress@4");
+      osmesaGetProcAddress = (PFNOSMESAGETPROCADDRESSPROC) GetProcAddress(oglImage, "OSMesaGetProcAddress");
     }
   }
   if (NULL != oglImage) {
     proc = (void*) GetProcAddress(oglImage, (LPCSTR) name);
   }
   if (NULL == proc) {
     if (osmesaGetProcAddress) {
       proc = osmesaGetProcAddress(name);
     }
     else {
@@ skipping 12906 matching lines @@
         }
 #endif
       }
     }
     ret = (len == 0);
   }
   return ret;
 }
 
 #endif /* _WIN32 */