introduce common.m4

introduce common.m4

It has bothered me for a while that files in common/ use macros
defined via autoconf checks, but rely on each configure.ac doing the
proper checks independently.

This patch introduces common/common.m4 which consolidates the checks
assumed by code in common.

The rule I propose is that if something is needed or used by common,
it should be checked for by common.m4.  However, if the check is also
needed by gdb or gdbserver, then it should be duplicated there.

Built and regtested on x86-64 Fedora 18 (though this is hardly the
most strenuous case) and using the Fedora 18 mingw cross compilers.  I
also examined the config.in diffs to ensure that symbols did not go
missing.

2013-11-08  Tom Tromey  <tromey@redhat.com>

	* acinclude.m4: Include common.m4.
	* common/common.m4: New file.
	* configure, config.in: Rebuild.
	* configure.ac: Use GDB_AC_COMMON.

2013-11-08  Tom Tromey  <tromey@redhat.com>

	* acinclude.m4: Include common.m4, codeset.m4.
	* configure, config.in: Rebuild.
	* configure.ac: Use GDB_AC_COMMON.