re PR c++/71537 (GCC rejects consetxpr boolean conversions and comparisons on the result of pointer arithmetic.)

	PR c++/71537
	* fold-const.c (maybe_nonzero_address): Return 1 for function
	local objects.
	(tree_single_nonzero_warnv_p): Don't handle function local objects
	here.

	* g++.dg/cpp1y/constexpr-71537.C: New test.

From-SVN: r244333