Monkey-patch program_name into gnulib

gnulib-program_name.patch

diff --git a/gnulib/lib/error.c b/gnulib/lib/error.c
index 18ff5db..d8c5acb 100644
--- a/gnulib/lib/error.c
+++ b/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