Fix win scons

[NQNStudios]

There's some messiness in this PR with trying things, reverting them, etc. It should probably all be squashed, but I can now make a build with scons on Windows that actually launches.

[NQNStudios]

I can't get the 32-bit build to work locally despite quadruple-checking all the lib paths. The compiler isn't finding Zlib, but I'm 100% sure I have an x86 build of zlib installed where scons is checking for it. This is frustrating.

I want to suggest separating out some concerns.

Without the PR, we have these problems:

• [ ] impossible to make a 32-bit build with scons on windows
• [ ] impossible to make a 64-bit build with scons on windows
• [ ] no installer generated by any Windows build
• [ ] windows scons logic missing so many required steps, I struggle to imagine how it ever worked, and/or what manual steps were required locally to make it work, but aren't documented anywhere
• [ ] unwanted DLLs required by the windows builds

With the PR, the situation becomes:

• [x] impossible to make a 64-bit build with scons on windows
• [x] windows scons logic missing so many required steps, I struggle to imagine how it ever worked, and/or what manual steps were required locally to make it work, but aren't documented anywhere
• [ ] impossible to make a 32-bit build with scons on windows
• [ ] no installer generated by any Windows build
• [ ] unwanted DLLs required by the windows builds

I would suggest that we do this:

1. Open an issue for the win-scons 32-bit build
2. Open an issue for the win-scons installer generation
3. Open an issue for the unwanted DLLs
4. Set the default win-scons build to 64-bit, so contributors following the README should get a successful result by default
5. Merge the PR

[CelticMinstrel]

I struggle to imagine how it ever worked

I'm not certain that it ever worked. When I built on Windows, I (almost?) always used MSVC 2013, not scons.

I agree on points 1, 3, and 4. For point 2, I would like the installer generation uncommented, but it can be set to run only if explicitly requested (so, running scons won't try to generate an installer, but running something like scons package will).

[NQNStudios]

I did all the things.

[CelticMinstrel]

Is it okay to squash all of this into a single commit? And if so, do you want to write up a summarized commit message?

[NQNStudios]

I'm pretty comfortable squashing all of this one without doing a summary. 🤷‍♀️