Right now the Makefile is cluttered with OS X equivalents
of all the x86 targets. We can get rid of all of them and
just check UNAME against "Darwin" for the few OS X-specific
things we need to do.
We also disable Clang LTO when using BMI2 instructions. For
some reason, LLVM cannot find the PEXT instruction when using
LTO. I don't know why, but disabling LTO for BMI2 fixes it.
No functional change.
Add a Mac SSE4.2 target. Also change the Mac OS X minimum version to
10.6. Rationale: 97% of Macs run at least 10.6, version 10.9 is now
free, and using 10.6 as the minimum version gives a small 5% boost in
benchmark speed over versions using 10.0 as the minimum version.
Finally, enable Clang’s Link Time Optimization when compiling for the
Mac.
No functional change.
Daylen Yang