[libcxx] Prefer C++14 over C++11 when building libc++experimental.
Summary:
Currently libc++experimental builds with C++11. This patch changes that to C++14 when supported by the compiler. Although nothing currently requires C++14 the upcoming <experimental/memory_resource> implementation would benefit from it. [1]
Note that libc++.so continues to build with C++11 and is unaffected by this change.
[1] <experimental/memory_resource> provides global resources which must exist for the entire lifetime of the program. In order to ensure that a global resource can be used during program termination there destructors must never be invoked. The only way to do this, while also allowing "constant initialization", is to use a C++14 union.
Reviewers: mclow.lists
Subscribers: pete, cfe-commits
Differential Revision: http://reviews.llvm.org/D19992
llvm-svn: 269070
2 files changed
