* Makefile.in (GTHREAD_FLAGS): New var.
	(LIBGCC2_CFLAGS): Added $(GTHREAD_FLAGS).
	(distclean): Remove gthr-default.h.
	* configure.in: Accept dce as a thread package.
	Check for thread.h and pthread.h.
	Link gthr-default.h to appropriate thread file and set
	gthread_flags.
	(hppa1.1-*-hpux10*): If --enable-threads, use dce threads and
	include multilib definitions from pa/t-dce-thr.
	(sparc-*-solaris2*): Enable threads by default, if thread.h or
	pthread.h is found, preferring posix threads over solaris ones.
	* config/pa/t-dce-thr: New file.
	* config/pa/t-pa: Removed multilibs.
	* config/sparc/t-sol2: Ditto.
	* gthr.h: New file.
	* gthr-single.h: New file.
	* gthr-posix.h: New file.
	* gthr-solaris.h: New file.
	* gthr-dce.h: New file.
	* libgcc-thr.h: Removed.
	* objc/thr-dce.c: New file copied from thr-decosf1.c.
	* frame.c: Include gthr.h instead of libgcc-thr.h.
	* libgcc2.c: Include gthr.h instead of libgcc-thr.h.
	(eh_context_initialize): If __gthread_once fails, use static eh
	context.
	(eh_context_free): Call __gthread_key_dtor.

From-SVN: r17235