diff -ruN gnulib.orig/lib/unistd.in.h gnulib/lib/unistd.in.h
--- gnulib.orig/lib/unistd.in.h	2014-11-06 14:52:50.973180715 +0100
+++ gnulib/lib/unistd.in.h	2014-11-06 14:54:20.485231338 +0100
@@ -401,6 +401,13 @@
 /* Set of environment variables and values.  An array of strings of the form
    "VARIABLE=VALUE", terminated with a NULL.  */
 #  if defined __APPLE__ && defined __MACH__
+#   include "TargetConditionals.h"
+#   if !defined(TARGET_OS_IPHONE) && !defined(TARGET_IPHONE_SIMULATOR)
+#     define APPLE_USE_CRT_EXTERNS
+#   endif
+#  endif
+#
+#  ifdef APPLE_USE_CRT_EXTERNS
 #   include <crt_externs.h>
 #   define environ (*_NSGetEnviron ())
 #  else