Makefile.am (libatomic_la_LDFLAGS): Add lt_host_flags.

	* Makefile.am (libatomic_la_LDFLAGS): Add lt_host_flags.
	* configure.ac (ACX_LT_HOST_FLAGS): New.
	(target_thread_file): New.
	* configure.tgt (mingw): Add mingw support.
	* config/mingw/host-config.h: New file.
	* config/mingw/lock.c: Likewise.
	* Makefile.in: Regenerated.
	* configure: Likewise.
	* aclocal.m4: Likewise.
	* testsuite/Makefile.in: Likewise.

From-SVN: r211747