How to build helix for windows-gnu target

[rcorre]

For #6425 (comment), I'm trying to build helix for windows using a GNU toolchain instead of MSVC.

I installed the 1.65-x86_64-pc-windows-gnu toolchain using rustup.
When I try to build helix, I get:

...
Compiling syn v2.0.15
error: failed to run custom build command for `num-traits v0.2.15`

Caused by:
  process didn't exit successfully: `C:\Users\rrc\src\helix\target\release\build\num-traits-660ad6392797043a\build-script-build` (exit code: 101)
  --- stderr
  thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error { kind: Io(Error { kind: NotFound, message: "program not found" }) }', C:\Users\rrc\.cargo\registry\src\github.com-1ecc6299
db9ec823\autocfg-1.1.0\src\lib.rs:128:20
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...
error[E0277]: the trait bound `proc_macro2::TokenStream: From<proc_macro::TokenStream>` is not satisfied
  --> C:\Users\rrc\.cargo\registry\src\github.com-1ecc6299db9ec823\syn-2.0.15\src\buffer.rs:69:20
   |
69 |         Self::new2(stream.into())
   |                    ^^^^^^ ---- required by a bound introduced by this call
   |                    |
   |                    the trait `From<proc_macro::TokenStream>` is not implemented for `proc_macro2::TokenStream`
   |
   = help: the trait `From<proc_macro2::TokenTree>` is implemented for `proc_macro2::TokenStream`
   = note: required for `proc_macro::TokenStream` to implement `Into<proc_macro2::TokenStream>`

error[E0277]: the trait bound `proc_macro2::TokenStream: From<proc_macro::TokenStream>` is not satisfied
    --> C:\Users\rrc\.cargo\registry\src\github.com-1ecc6299db9ec823\syn-2.0.15\src\parse.rs:1207:52
     |
1207 |         self.parse2(proc_macro2::TokenStream::from(tokens))
     |                     ------------------------------ ^^^^^^ the trait `From<proc_macro::TokenStream>` is not implemented for `proc_macro2::TokenStream`
     |                     |
     |                     required by a bound introduced by this call
     |
     = help: the trait `From<proc_macro2::TokenTree>` is implemented for `proc_macro2::TokenStream`

For more information about this error, try `rustc --explain E0277`.
error: could not compile `syn` due to 2 previous errors
error: failed to compile `helix-term v0.6.0 (C:\Users\rrc\src\helix\helix-term)`, intermediate artifacts can be found at `C:\Users\rrc\src\helix\target`

Has anyone compiled helix for the windows-gnu target?

[rcorre]

I was able to get it to compile by running in the MSYS2 mingw64 environment