make_location: ensure end-points are pure locations

make_location: ensure end-points are pure locations

gcc/ChangeLog:
	* input.c (make_location): Call get_start and get_finish
	on the endpoints to avoid storing packed ranges or ad-hoc
	ranges in them.
	(selftest::test_make_location_nonpure_range_endpoints): New function.
	(selftest::input_c_tests): Call it.
	* input.h (get_start): New inline function.

From-SVN: r239831