In some cases, gcc-11 does a good enough job translating normal looking
C expressions so use just those, but other times need to dig around for
an appropriate intrinsic.
Also, now need to disable psapi warnings when compiling for anything
less than avx.
For int, long, float and double. I've been meaning to add them for a
while, and they're part of the new Ruamoko instructions set (which is
progressing nicely).
