Update macOS deployment target to 10.9.
Targeting 10.9 from a 10.10 bot is the configuration the NDK is
It seems that to update to anything newer we probably need to change
how we're configuring binutils. I think this is related to the fact
that `xcode-select --install` no longer installs the sysroot to
/usr/local/include, and that's probably what our old GCC prebuilts are
1 file changed