* include/private/gcconfig.h: Add unified test for FreeBSD.

	Support FreeBSD/alpha.
	* os_dep.c: Do not include <machine/trap.h> unless available.
	(GC_freebsd_stack_base): Fix types.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@51159 138bc75d-0d04-0410-961f-82ee72b054a4