http://sourceware.org/ml/gdb-patches/2013-08/msg00340.html
gdb/ChangeLog
* common/format.c (parse_format_string): Don't allow '#' flag for
pointer arguments in format string.
gdb/testsuite/ChangeLog
* gdb.base/printcmds.exp (test_printf): Add test for printf of
pointer with various flags.