Sourcing /etc/gdb.conf is annoying mainly because Apple put
  set history save on
in there, which means everywhere you run it, you end up with a
.gdb_history file.

--- src/gdb/main.c
+++ src/gdb/main.c
@@ -675,6 +675,7 @@
   memset (&cwdbuf, 0, sizeof (struct stat));
   /* APPLE LOCAL end move inits up */
   /* APPLE LOCAL begin global gdbinit */
+#ifdef WANT_GLOBAL_GDBINIT
   memset (&globalbuf, 0, sizeof (struct stat));
   stat (gdbinit_global, &globalbuf);
   if (!inhibit_gdbinit)
@@ -683,6 +684,7 @@
 	 source_file (gdbinit_global, 0);
     }
   do_cleanups (ALL_CLEANUPS);
+#endif
   /* APPLE LOCAL end global gdbinit */
  
   /* APPLE LOCAL: Set the $_Xcode convenience variable at '0' before sourcing