On mainline/development, also link GDBserver with -lmcheck.

This factors --enable-libmcheck related bits from GDB's configure.ac
and makes GDBserver use them too.  Specifically, the 'development'
global is moved to a separate script to it can be sourced by both GDB
and GDBserver, and the --enable-libmcheck/--disable-libmcheck bits
proper are moved to a new m4 file.

I started out by defining 'development' in the m4 file, but in the end
decided against it, as a separate script has the advantage that
changing it in release branches does not require regenerating
configure, unlike today.

I had also started out by making the new GDB_AC_LIBMCHECK itself
handle the yes/no default fallback depending on release/developement,
but since I had split out 'development' to a separate script, and, GDB
needs the python checks anyway (hence we'd need to do the python
checks in gdb's configure.ac, and pass in a 'default lmcheck yes/no'
parameter to GDB_AC_LIBMCHECK anyway), I ended up keeping
GDB_AC_LIBMCHECK isolated from the 'development' global.  IOW, it's
the caller's business to handle it.

Tested on x86_64 Fedora 17.  Built GDB and GDBserver with and without
--enable-libmcheck, and observed --enable-libmcheck overrides the
disablement of -lmcheck caused by python supporting threads, and that
GDBserver links with -lmcheck when expected.  Also observed that
changing the 'development' global, and issuing "make" triggers a
relink, and '-lmcheck' is included or not from the link accordingly.

gdb/
2013-07-03  Pedro Alves  <palves@redhat.com>

	* Makefile.in (config.status): Depend on development.sh.
	(aclocal_m4_deps): Add libmcheck.m4.
	* acinclude.m4: Include libmcheck.m4.
	* configure.ac: Source development.sh instead of setting
	'development' here.  --enable-libmcheck/--disable-libmcheck code
	factored out to GDB_AC_LIBMCHECK.  Run it.
	* development.sh: New file.
	* libmcheck.m4: New file.
	* configure: Regenerate.

gdb/gdbserver/
2013-07-03  Pedro Alves  <palves@redhat.com>

	* Makefile.in (config.status): Depend on development.sh.
	* acinclude.m4: Include libmcheck.m4.
	* configure: Regenerate.