[PATCH] D25491: [libcxx] Use C++14 when building libc++ with musl

[Eric Fiselier via cfe-commits]

EricWF added a comment.

> musl's pthread implementations use volatile types in their structs which is not being constexpr in C++11 but is in C++14.

This means that libc++'s std::mutex is unsafe to use during dynamic initialization in C++11 with MUSL, which would really suck except that Clang emits always emits the initialization as a constant expression, ever if it's not guaranteed by the core language.

@mclow.lists Do you have any issue bumping the std version while building for MUSL only?



================
Comment at: CMakeLists.txt:327
 # Required flags ==============================================================
 set(LIBCXX_STANDARD_VER c++11 CACHE INTERNAL "internal option to change build dialect")
 add_compile_flags_if_supported(-std=${LIBCXX_STANDARD_VER})
----------------
Why not just set `LIBCXX_STANDARD_VER` differently instead of replacing it after the fact?


Repository:
  rL LLVM

https://reviews.llvm.org/D25491