Restore Windows support

[conradoplg]

#37 removed Windows support because it was requiring a lot of work but we don't support Windows in Zebra anyway.

Restore Windows support.

This is what I tried before giving up:

• Windows require compiling and linking to bundlecache.c (I have no idea how it works on Linux)
  • That requires compiling and linking src/zcash/cache.cpp, which requires Boost, which is super annoying
  • If you comment out the parts of orchard_ffi.rs that don't handle orchard_bundle (i.e. orchard_batch_*) then you can get away with not including bundlechache.c. But that leads to other problems:

    • Running the test results in STATUS_ENTRYPOINT_NOT_FOUND which seems to be this.

      • To work around that, adding a manifest as described there using the embed-manifest crate results in

      error: invalid instruction `cargo:rustc-link-arg-bins` from build script of `zcash_script v0.1.6 (D:\a\zcash_script\zcash_script)`
      Error: The package zcash_script v0.1.6 (D:\a\zcash_script\zcash_script) does not have a bin target.
      Error: The process 'C:\Users\runneradmin\.cargo\bin\cargo.exe' failed with exit code 101
      

      The code I used was (it's also in windows-support-attempt branch)

      if std::env::var_os("CARGO_CFG_WINDOWS").is_some() {
          embed_manifest(
              new_manifest("zcash_script").dependency(AssemblyIdentity::new(
                  "Microsoft.Windows.Common-Controls",
                  [6, 0, 0, 0],
                  0x6595b64144ccf1df,
              )),
          )
          .expect("unable to embed manifest file");
      }

[oxarbitrage]

I was making some quick tests here, it seems there are at least 4 undefined references that we need to fix to restore support:

• undefined reference to `CFeeRate::GetFee(unsigned long long) const'
• undefined reference to `CalculateConventionalFee(unsigned long long)'
• undefined reference to `CalculateLogicalActionCount(std::vector<CTxIn, std::allocator > const&, std::vector<CTxOut, std::allocator > const&, unsigned int, unsigned int, unsigned int, unsigned int)'
• undefined reference to `libzcash::NewBundleValidityCache(rust::cxxbridge1::Str, unsigned long long)'

https://github.com/ZcashFoundation/zcash_script/actions/runs/6502088364/job/17660515982#step:6:21482