re PR driver/48306 (presence of gcc subdir with . in PATH causes breakdown)

re PR driver/48306 (presence of gcc subdir with . in PATH causes breakdown)

	* make-relative-prefix.c (make_relative_prefix_1): Avoid
	stack overflow if PATH contains just a single entry and
	HOST_EXECUTABLE_SUFFIX needs to be used.

	PR driver/48306
	* make-relative-prefix.c: Include sys/stat.h.
	(make_relative_prefix_1): If access succeeds, check also stat
	if nstore is a regular file.

From-SVN: r182820