testsuite/glib-2.34: Match/consume optional libthread_db related output

When using glibc-2.34, we now see messages related to the loading of
the thread library for non-thread programs.  E.g.  for the test case,
gdb.base/execl-update-breakpoints.exp, we will see the following when
starting the program:

(gdb) break -qualified main
Breakpoint 1 at 0x100118c: file /ironwood1/sourceware-git/f34-2-glibc244_fix/bld/../../worktree-glibc244_fix/gdb/testsuite/gdb.base/execl-update-breakpoints.c, line 34.
(gdb) run
Starting program: [...]/execl-update-breakpoints1
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

The two lines of output related to libthread_db are new; we didn't see
these in the past.  This is a side effect of libc now containing the
pthread API - we can no longer tell whether the program is
multi-threaded by simply looking for libpthread.so.  That said, I
think that we now want to load libthread_db anyway since it's used to
resolve TLS variables; i.e. we need it for correctly determining the
value of errno.

This commit adds the necessary regular expressions to match this
(optional) additional output in the two tests which were failing
without it.

gdb/testsuite/ChangeLog:

	* gdb.base/execl-update-breakpoints.exp: Add regular
	expression for optionally matching output related to
	libthread_db.
	* gdb.base/fork-print-inferior-events.exp: Likewise.

0 files changed, 0 insertions, 0 deletions