Regenerate gdb/configure and gdbserver/configure

Regenerate gdb/configure and gdbserver/configure

Pedro pointed out that gdb/configure and gdbserver/configure weren't
updated after some recent *.m4 changes.

This patch rebuilds those files.  Tested by rebuilding.  Pedro
approved this in the thread where he raised this issue, so I'm pushing
it in.

ChangeLog
2018-04-23  Tom Tromey  <tom@tromey.com>

	* configure: Rebuild.

gdbserver/ChangeLog
2018-04-23  Tom Tromey  <tom@tromey.com>

	* configure: Rebuild.