Add warning if fips libcrypto is built on MacOS
Add warning if fips libcrypto is built on MacOS

FIPS is not officially supported on the platform. The script supports it
as a convenience for s2n developers who work on MacOS locally.

awslabs/s2n,PKRoma/s2n,alexeblee/s2n,colmmacc/s2n,jldodds/s2n,raycoll/s2n,gibson-compsci/s2n,colmmacc/s2n,alexeblee/s2n,raycoll/s2n,wcs1only/s2n,wcs1only/s2n,PKRoma/s2n,PKRoma/s2n,gibson-compsci/s2n,raycoll/s2n,bpdavidson/s2n,colmmacc/s2n,bpdavidson/s2n,raycoll/s2n,jldodds/s2n,gibson-compsci/s2n,awslabs/s2n,alexeblee/s2n,wcs1only/s2n,colmmacc/s2n,PKRoma/s2n,PKRoma/s2n,wcs1only/s2n,awslabs/s2n,bpdavidson/s2n,bpdavidson/s2n,jldodds/s2n,bpdavidson/s2n,raycoll/s2n,jldodds/s2n,gibson-compsci/s2n,awslabs/s2n,PKRoma/s2n,awslabs/s2n,wcs1only/s2n,wcs1only/s2n,gibson-compsci/s2n,alexeblee/s2n,colmmacc/s2n,wcs1only/s2n,colmmacc/s2n,alexeblee/s2n,gibson-compsci/s2n,PKRoma/s2n,raycoll/s2n,bpdavidson/s2n,wcs1only/s2n,PKRoma/s2n,awslabs/s2n,jldodds/s2n,alexeblee/s2n