Windows build support

[dneto0]

Builds on #59

And then also:

• force static linking of C Runtime into executables
• Use fopen_s to avoid security warning in MSVC

This version completes the build, then fails a unit test.

[dneto0]

I think the Windows build support is ready now.

Getting failures on Linux and Windows, as described by the bots:

[ RUN      ] CommandParserTest.MaxDepthBounds
1093
../src/vkscript/command_parser_test.cc:1666: Failure
1094
Expected equality of these values:
1095
  3.f
1096
    Which is: 3
1097
  cp.PipelineDataForTesting()->GetMaxDepthBounds()
1098
    Which is: 3.4000001
1099
[  FAILED  ] CommandParserTest.MaxDepthBounds (0 ms)

I don't know where that's coming from. I tried a GCC UBSAN debug build and it didn't catch the problem. ???

[dneto0]

Ok. The test had been accidentally broken by the first commit in this MR. :-)

[dj2]

Hah, nice find. And oops.