re PR c++/47774 ([C++0x] constexpr specifier on ctor not ignored when template instantiation causes ctor to not satify constexpr requirements)
PR c++/47774
* tree.c (build_vec_init_elt): Split out from...
(build_vec_init_expr): ...here.
(diagnose_non_constexpr_vec_init): New fn.
* semantics.c (potential_constant_expression_1): Use it.
* cp-tree.h: Declare it.
From-SVN: r170638
