https://lists.gnu.org/archive/html/bug-gnulib/2015-02/msg00079.html

From: Margaret Lewicka <address@hidden>

---
 lib/error.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/error.c b/lib/error.c
index 6683197..36a3db7 100644
--- a/gnulib/lib/error.c
+++ a/gnulib/lib/error.c
@@ -113,9 +113,13 @@ int strerror_r ();
 #  endif
 # endif
 
+#if defined __APPLE__ && defined __MACH__
+#define program_name (((char **)*_NSGetArgv())[0])
+#else
 /* The calling program should define program_name and set it to the
    name of the executing program.  */
 extern char *program_name;
+#endif
 
 # if HAVE_STRERROR_R || defined strerror_r
 #  define __strerror_r strerror_r
-- 
2.1.0