diff --git a/auto/src/glew_init_tail.c b/auto/src/glew_init_tail.c
index 0ef2ad8..f0e2573 100644
--- a/auto/src/glew_init_tail.c
+++ b/auto/src/glew_init_tail.c
@@ -41,7 +41,7 @@ GLenum GLEWAPIENTRY glewInit (void)
   if ( r != 0 ) return r;
 #if defined(GLEW_OSMESA)
   return r;
-#if defined(_WIN32)
+#elif defined(_WIN32)
   return wglewInit();
 #elif !defined(__ANDROID__) && !defined(__native_client__) && !defined(__HAIKU__) && (!defined(__APPLE__) || defined(GLEW_APPLE_GLX)) /* _UNIX */
   return glxewInit();