We currently target OS X 10.6 when building the server. 10.6 is the last revision of OS X where the default toolchain is GCC 4.2.

If we can upgrade our target minimum to 10.7 we will pick up the newer clang toolchain which supports C++11.

This would also allow us to eliminate the special C+11 OS X builder, as the regular OS X build would automatically use C+11.