re PR c++/83692 (Rejects valid constexpr with unrelated code fixing problem)

re PR c++/83692 (Rejects valid constexpr with unrelated code fixing problem)

	PR c++/83692
	* constexpr.c (maybe_constant_init_1): New function.
	(maybe_constant_init): Make it a wrapper around maybe_constant_init_1.
	(cxx_constant_init): New function.
	* cp-tree.h (cxx_constant_init): Declare.
	* typeck2.c (store_init_value): Call cxx_constant_init instead of
	cxx_constant_value.  Move the maybe_constant_init call under an 'else'.

	* g++.dg/cpp1z/constexpr-83692.C: New test.

From-SVN: r257961