## Summary
Adds a unified mechanism for locating third-party IO DLLs through environment
variables, on top of the existing per-game `[xxxio] path=` INI setting.
## Changes
For each IO DLL, the path is resolved in this order:
1. The section-specific INI value, e.g. `[mai2io] path=`.
2. The section-specific environment variable, e.g. `SEGATOOLS_MAI2IO_PATH`.
3. `SEGATOOLS_IO_ROOT` joined with the default IO DLL filename, e.g.
`%SEGATOOLS_IO_ROOT%\mai2io.dll`.
4. Empty path, which keeps the built-in IO implementation (unchanged default).
INI and environment-variable paths are run through Windows environment-variable
expansion, so values such as `%SEGATOOLS_IO_ROOT%\mai2io.dll` are valid in the
INI directly.
Reviewed-on: https://gitea.tendokyu.moe/TeamTofuShop/segatools/pulls/119
Co-authored-by: グローランプ <130208311+Gl0w1amp@users.noreply.github.com>
Co-committed-by: グローランプ <130208311+Gl0w1amp@users.noreply.github.com>
[UnityDoorstop](https://github.com/NeighTools/UnityDoorstop) is a tool to execute managed code (.NET DLLs) before Unity does, useful for modding frameworks such as BepInEx.
This PR integrates parts of its code into segatools, so loading BepInEx is as simple as adding 2 lines to `segatools.ini`:
```ini
[unity]
targetAssembly=BepInEx\core\BepInEx.Preloader.dll
```
This PR also factors out the Unity path redirection hooks to its own module.
Reviewed-on: https://gitea.tendokyu.moe/Dniel97/segatools/pulls/11
Co-authored-by: beerpsi <beerpsi@duck.com>
Co-committed-by: beerpsi <beerpsi@duck.com>
グローランプ