When building on win32 systems, simply add the win32 specific functions
to the libn2n.a, which simplifies the commands needed.
By moving the win32 source code into the src directory, the source code
is better consolidated.
If there is a way to turn off the mingw insistence that it will rewrite
the filename it was given in the "-o" options, I have not been able to
find it. I could easily handle all the moves or renames at the end of
the build process if I could turn off this feature. Especially since it
means that make often thinks that the file has not been built (the
filename that make knows about is not the file that actually gets built
by the mingw gcc, so the if-newer tests that make applies will always
fail)
It looks like the github windows build environment is not correctly
inheriting environment variables. Which is strange, as that has not
been changed with the recent updates. Include the vars directly as a
workaround (and plan to refactor later)
