should define FUNC_CDECL/STDCALL if the macros are not defined.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@10484 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/dl/dl.h

@@ -3,6 +3,13 @@
 
 #include <ruby.h>
 
+#if !defined(FUNC_CDECL)
+#  define FUNC_CDECL(x) x
+#endif
+#if !defined(FUNC_STDCALL)
+#  define FUNC_STDCALL(x) x
+#endif
+
 #if defined(HAVE_DLFCN_H)
 # include <dlfcn.h>
 # /* some stranger systems may not define all of these */