Index: missing/setproctitle.c
===================================================================
--- missing/setproctitle.c	(revision 35272)
+++ missing/setproctitle.c	(working copy)
@@ -36,6 +36,10 @@
 #include "ruby/util.h"
 #define compat_init_setproctitle ruby_init_setproctitle
 
+#ifdef __APPLE__
+#include <crt_externs.h>
+#endif
+
 #ifndef HAVE_SETPROCTITLE
 
 #include <stdarg.h>
@@ -72,7 +76,13 @@
 compat_init_setproctitle(int argc, char *argv[])
 {
 #if defined(SPT_TYPE) && SPT_TYPE == SPT_REUSEARGV
+
+#ifdef __APPLE__
+#undef environ
+#define environ (*_NSGetEnviron())
+#else
 	extern char **environ;
+#endif
 	char *lastargv = NULL;
 	char *lastenvp = NULL;
 	char **envp = environ;