Added the __ANSI_STRICT definition for OSX

The __ANSI_STRICT defintion is necessary because it avoids the
creation of the std::numeric_limits<__128> template in the
<limits> header.
Compile using g++ on OSX

The Accelerate framework requires -flax-vector-conversions to
compile on g++
Fix g++ warnings on OSX
Merge pull request #271 from umar456/osx_build

Fix errors and warnings on OSX