diff --git a/src/if_ruby.c b/src/if_ruby.c
index 6bb8b80..8dd6064 100644
--- a/src/if_ruby.c
+++ b/src/if_ruby.c
@@ -54,7 +54,7 @@
 #undef _
 
 /* T_DATA defined both by Ruby and Mac header files, hack around it... */
-#ifdef MACOS
+#if defined(MACOS_X_UNIX) || defined(macintosh)
 # define __OPENTRANSPORT__
 # define __OPENTRANSPORTPROTOCOL__
 # define __OPENTRANSPORTPROVIDERS__