gcc.c (add_sysrooted_prefix, [...]): Use fatal, not abort.

	* gcc.c (add_sysrooted_prefix, execute, do_self_spec, do_spec_1,
	handle_braces, process_brace_body, main, used_arg,
	set_multilib_dir, print_multilib_info): Use fatal, not abort.

From-SVN: r87231