Port accumulated updates from msun to openlibm

[ViralBShah]

We have about 2 years worth of accumulated updates in freebsd msun that we need to port to openlibm. Seeing that the initial commit was from Aug 13 2011, I think we need to see what else is worth getting from that point onwards.

https://github.com/freebsd/freebsd/commits/master/lib/msun?page=6

I don't think there is too much to be done, but it has to be carefully done.

[ViralBShah]

I scanned through the commit log. It largely consists of i386 and arm updates. I also noticed the addition of expl, which we do not have.

[ViralBShah]

#118