Win32 build - stage 1. Core bootstrap.

[wlvchandler]

(Resubmitted with correct history)

Note - this is only the bootstrap portion to get a starting point for proper windows acr support. It successfully builds abt, src_hdr, src_func, and gcache build, but abt dies on an early error right now (will be handled in "stage 2"). the other binaries work as intended, verified by

1. I wrapped all changes to cpp in #if defined(WIN32) blocks. I believe some of these changes would cause 0 issues on *nix builds - for example, casting - but better safe than sorry for now. That testing can occur later.
2. The win32 build doesn't fit with the current workflow yet, so I added windows-specific .bat files. Dependencies are still being worked out, but this current commit just requires an openssl download (I added a script for a portable Perl download as well but it's unused)
3. It does not work with MSVS GUI yet (at least, I haven't tried) - so the build process is running bin/win-ai.bat from the command line (works on CMD, PS and MSVS Dev command prompt):
4. All 4 executables build, but the linker reports the following issues (TODO for next stage):
   • error LNK2019: unresolved external symbol
     • workaround for now: /FORCE:unresolved in linker argument (causes LNK4088 warning)
       • algo::Attr_ReadStrptrMaybe is user-defined
       • gcache: openssl/EVP symbols, Sha1Ctx::Sha1Ctx
   • warning LNK4042: object specified more than once; extras ignored
     • all lib.algo object files. not causing issues, but annoying
   • warning LNK4006: already defined in

[wlvchandler]

(force-pushed a change w/ updated gitfile)