Update glibc_thread_db.h from upstream.

Update glibc_thread_db.h from upstream.

Attempting to build gdbserver with our copy of thread_db.h yields:

In file included from ../../../src/gdb/gdbserver/../common/gdb_thread_db.h:4:0,
                 from ../../../src/gdb/gdbserver/thread-db.c:30:
../../../src/gdb/gdbserver/../common/glibc_thread_db.h:108:3: error: unknown type name ‘uint32_t’
In file included from ../../../src/gdb/gdbserver/../common/gdb_thread_db.h:4:0,
                 from ../../../src/gdb/gdbserver/thread-db.c:30:
../../../src/gdb/gdbserver/../common/glibc_thread_db.h:199:5: error: unknown type name ‘uintptr_t’
../../../src/gdb/gdbserver/../common/glibc_thread_db.h:269:3: error: unknown type name ‘intptr_t’
../../../src/gdb/gdbserver/../common/glibc_thread_db.h:270:3: error: unknown type name ‘intptr_t’

We used to have a workaround for this, but the patch to import
gnulib's stdint.h removed it:

  http://www.sourceware.org/ml/gdb-patches/2008-06/msg00050.html

and defs.h made to always include stdint.h.  However, gdbserver
doesn't include stdint.h in its equivalent server.h.

Rather than working around the issue, I've imported a more recent
version from glibc, which itself includes <stdint.h>.  Other than
copyright years and FSF snail mail address, the file hasn't been
touched since 2003 in glibc.  AFAICS, our version was updated last in
2000-09-03.

A note on the apparent license change: before the previous patch, this
file's contents were part of gdb_thread_db.h, and we can see that its
license's text was changed in this patch
<http://sourceware.org/ml/gdb-patches/2009-03/msg00251.html>.  That
was certainly just an easy to overlook grep/sed mistake that fell
through the cracks.

gdb/common/
2013-04-16  Pedro Alves  <palves@redhat.com>

	* glibc_thread_db.h: Update from upstream glibc
	(git 568035b7874a099087b77f7bba3e36a1173787b0).