Add private option to change build dialect from C++11

Although libc++ only requires C++11 to build, there are other
reasons to turn on a newer dialect in the build. For example
IDE's may not highlight any C++14/C++17 in the headers when
configured for C++11. This patch add's a private option for
changing this.





git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@278638 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed