add libcc1

This patch adds the plugin to the gcc tree and updates the top-level
configury.

It seems better to have this code in the gcc tree than in the gdb
tree, because it is bound more tightly to gcc.  The gcc plugin makes
direct calls into various parts of gcc to do its work; whereas on the
gdb side everything is done via a relatively simple API, without any
direct connection to gdb internals.  This breakdown made the most
sense because most calls are from gdb to gcc rather than vice versa.

The plugin itself consists of two parts.  These parts communicate via
a simple ad hoc RPC system implemented in the plugin code.

2014-06-19  Phil Muldoon  <pmuldoon@redhat.com>
	    Tom Tromey  <tromey@redhat.com>

	* Makefile.def: Add libcc1 to host_modules.
	* configure.ac (host_tools): Add libcc1.
	* Makefile.in, configure: Rebuild.

2014-06-19  Phil Muldoon  <pmuldoon@redhat.com>
	    Jan Kratochvil  <jan.kratochvil@redhat.com>
	    Tom Tromey  <tromey@redhat.com>

	* aclocal.m4: New file.
	* callbacks.cc: New file.
	* callbacks.hh: New file.
	* cc1plugin-config.h.in: New file.
	* configure: New file.
	* configure.ac: New file.
	* connection.cc: New file.
	* connection.hh: New file.
	* findcomp.cc: New file.
	* findcomp.hh: New file.
	* libcc1.cc: New file.
	* libcc1plugin.sym: New file.
	* libcc1.sym: New file.
	* Makefile.am: New file.
	* Makefile.in: New file.
	* marshall.cc: New file.
	* marshall.hh: New file.
	* names.cc: New file.
	* names.hh: New file.
	* plugin.cc: New file.
	* rpc.hh: New file.
	* status.hh: New file.