The [prerelease version of the Linux subsystem](https://docs.microsoft.com/windows/wsl/install-legacy) available in the 1607 and 1703 releases of Windows 10 is obsolete so consider uninstalling it.
Make sure that the `build-essential`, `git`, and `libpng-dev` packages are installed. The `build-essential` package includes the `make`, `gcc-core`, and `g++` packages so they do not have to be obtained separately. MSYS2 does not include `libpng-dev` so it must be built from source.
If you are *not* using MSYS2, install the **devkitARM** toolchain of [devkitPro](https://devkitpro.org/wiki/Getting_Started) and add its environment variables.
If the repository was previously set up using Cygwin, delete the `.exe` files in the subfolders of the `tools` folder except for `agbcc` and run the `build_tools.sh` script again.
If only `.c` or `.s` files were changed, turn off the dependency scanning temporarily. Changes to any other files will be ignored and the build will either fail or not reflect those changes.
**Note:** If the build command is not recognized on Linux, including the Linux environment used within Windows, run `nproc` and replace `$(nproc)` with the returned value (e.g.: `make -j4`). Because `nproc` is not available on macOS, the alternative is `sysctl -n hw.ncpu`.
**Note 2:** If the base tools are not found on macOS in new Terminal sessions after the first successful build, run `echo "if [ -f ~/.bashrc ]; then . ~/.bashrc; fi" >> ~/.bash_profile` once to prevent the issue from occurring again.
