[PATCH] Use __is_same_as for std::is_same and std::is_same_v

[Jonathan Wakely <jwakely at redhat dot com>]

By using the built-in we don't need to match a partial specialization
for std::is_same and don't need to instantiate std::is_same at all for
uses of std::is_same_v.

	* include/std/type_traits (is_same): Replace partial specialization
	by using __is_same_as built-in in primary template.
	(is_same_v): Use __is_same_as built-in instead of instantiating the
	is_same trait.

Tested x86_64-linux, committed to trunk.

Attachment: patch.txt
Description: Text document