Windows Support

[KJ7LNW]

There are alpha win32 commits in the win32 branch that compile under mingw.

This binary release is slow and choppy because fork() is missing, but does run under Windows 10!

If libltdl were implemented to replace dlopen in src/mathlib.c then OpenBLAS for Windows would probably be fast and multi-threaded.

If anyone is interested then comment here or open a PR. The current win32 branch was just a quick fix to get it building. A few necessary fixes before it can be merged:

• configure.ac should be cleaned up
• branch needs to be rebased on master
• apparently I committed those first two changes as root so we need to do a filter-branch with my correct email address and contact details.