Simplified extension loader
Simplified extension loader

Functions in both legacy and modern path; doesn't do any memory
allocations.  Caveat is that string processing on extension support
check is more expensive now.

Solution is to double back to what I was thinking earlier; modern path
stays as is, legacy path will copy extension string and pad with null
termination values where spaces should be.

Steve132/glhpp,VirtuosoChris/glhpp,VirtuosoChris/glhpp,Steve132/glhpp,Steve132/glhpp,VirtuosoChris/glhpp,Steve132/glhpp