PR debug/37959

	PR debug/37959
	* dwarf2out.c (dwarf_attr_name): Handle DW_AT_explicit attribute.
	(gen_subprogram_die): When a function is explicit, generate the
	DW_AT_explicit attribute.
	* langhooks.h (struct lang_hooks_for_decls): Add
	function_decl_explicit_p langhook.
	* langhooks-def.h (LANG_HOOKS_FUNCTION_DECL_EXPLICIT_P): Define.
	(LANG_HOOKS_DECLS): Add LANG_HOOKS_FUNCTION_DECL_EXPLICIT_P.

	* cp-objcp-common.h (LANG_HOOKS_FUNCTION_DECL_EXPLICIT_P): Define.
	(cp_function_decl_explicit_p): New prototype.
	* cp-objcp-common.c (cp_function_decl_explicit_p): New function.

	* g++.dg/debug/dwarf2/explicit-constructor.C: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@145128 138bc75d-0d04-0410-961f-82ee72b054a4