* call.c (build_converted_constant_expr_internal): New function,
	renamed from...
	(build_converted_constant_expr): ...this.  New.
	(build_converted_constant_bool_expr): New.
	* cp-tree.h (build_converted_constant_bool_expr): Declare.
	* decl.c (build_explicit_specifier): Call
	build_converted_constant_bool_expr.

	* g++.dg/cpp2a/explicit15.C: New test.

From-SVN: r270002