change libcxx +emultated_tls to installing a binary please on < 10.7...

[Ken Cunningham]

another reasonably simple option would be to have a manual step, and copy what happens with apple-gcc42 +bootstrap.


We make up a non-TLS variant of libcxx, call it libcxx +bootstrap, and default to installing that if there is nothing in /usr/lib/libc++.dylib.

Then the port notes (like apple-gcc42) would tell people what to do:

require the installation of clang-5.0, then run:

sudo port install libcxx -bootstrap

and that gets the binary installed.

From then on, people would just have to 

sudo port install libcxx 

and they would get the TLS version.

Ken