patched for Cygwin (Sven Panne)
diff --git a/include/GL/glut.h b/include/GL/glut.h
index 225bb87..20605cb 100644
--- a/include/GL/glut.h
+++ b/include/GL/glut.h
@@ -108,7 +108,7 @@
    and redifinition of Windows system defs, also removes requirement of
    pretty much any standard windows header from this file */
 
-#if (_MSC_VER >= 800) || defined(_STDCALL_SUPPORTED)
+#if (_MSC_VER >= 800) || defined(_STDCALL_SUPPORTED) || defined(__CYGWIN32__)
 #	define GLUTAPIENTRY __stdcall
 #else
 #	define GLUTAPIENTRY