tree 99b793a18894bb3eedeab96972a0b27e6bcc96c8
parent ef089063140d918a8ad77e3dc8120de6d3896d8d
author Eric Fiselier <eric@efcs.ca> 1556128465 +0000
committer Eric Fiselier <eric@efcs.ca> 1556128465 +0000

Add std::is_constant_evaluated.

Clang recently added __builtin_is_constant_evaluated() and GCC 9.0
has it as well.

This patch adds support for it in libc++.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@359119 91177308-0d34-0410-b5e6-96231b3b80d8