[guile] Run finalizers from GDB thread

[guile] Run finalizers from GDB thread

gdb/ChangeLog:

	* guile/guile.c (_initialize_guile): Disable automatic
	finalization, if Guile offers us that possibility.
	* guile/guile.c (call_initialize_gdb_module):
	* guile/scm-safe-call.c (gdbscm_with_catch): Arrange to run
	finalizers in appropriate places.
	* config.in (HAVE_GUILE_MANUAL_FINALIZATION): New definition.
	* configure.ac (AC_TRY_LIBGUILE): Add a check for
	scm_set_automatic_finalization_enabled.
	* configure: Regenerated.