PR c++/88815 - narrowing conversion lost in decltype.

	PR c++/88815 - narrowing conversion lost in decltype.
	PR c++/78244 - narrowing conversion in template not detected.
	* cp-tree.h (CONSTRUCTOR_IS_DEPENDENT): New.
	* pt.c (instantiation_dependent_r): Consider a CONSTRUCTOR with
	CONSTRUCTOR_IS_DEPENDENT instantiation-dependent.
	* semantics.c (finish_compound_literal): When the compound literal
	isn't instantiation-dependent and the type isn't type-dependent,
	fall back to the normal processing.  Set CONSTRUCTOR_IS_DEPENDENT.

	* g++.dg/cpp0x/Wnarrowing15.C: New test.
	* g++.dg/cpp0x/Wnarrowing16.C: New test.
	* g++.dg/cpp0x/constexpr-decltype3.C: New test.
	* g++.dg/cpp1y/Wnarrowing1.C: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@268321 138bc75d-0d04-0410-961f-82ee72b054a4