Commit 21a4710c67a97838dd75cf60ed24da11280800f8 previously enabled
LoopVectorization and SLPVectorization CodeGen options for the ELF and
COFF LTO backends. Since the Mach-O LTO port did not exist at the time,
it missed this configuration.
This patch adds these options to the Mach-O LTO setup for consistency
with the other backends. Without this, SLP and loop vectorization passes
are silently skipped during Mach-O LTO for O2 and O3 builds.
cb0b13d9d7