The new job indicated success, but didn't upload an executable.

This was because on the Windows runner, the default shell is PowerShell:

    Run ./.github/bin/install-zig
      ./.github/bin/install-zig
      shell: C:\Program Files\PowerShell\7\pwsh.EXE -command ". '{0}'"

Explicitly set the shell to bash for every cross compilation job.

Fix error:

    CC: configlet.nim
    Hint:  [Link]
    Hint: mm: refc; threads: on; opt: size; options: -d:release
    92399 lines; 54.815s; 167.895MiB peakmem; proj: D:\a\configlet\configlet\src\configlet.nim; out: D:\a\configlet\configlet\configlet.exe [SuccessX]
         Info:  Nimble data file "C:\Users\runneradmin\.nimble\nimbledata2.json" has been saved.
    stripping large comment section from executable...
    C:\Program Files\LLVM\bin\llvm-strip.exe: error: 'configlet': no such file or directory

(It turns out that `llvm-strip` is installed in the Windows runners).

Some llvm-strip usage:

  --remove-section=section
                         Remove <section>
  -R <value>             Alias for --remove-section
  --strip-all-gnu        Compatible with GNU's --strip-all
  --strip-all            Remove non-allocated sections outside segments. .gnu.warning* and .ARM.attribute sections are not removed
  --strip-debug          Remove all debug sections
  --strip-sections       Remove all section headers and all sections not in segments
  --strip-symbol=symbol  Strip <symbol>
  --strip-unneeded       Remove all symbols not needed by relocations
  -S                     Alias for --strip-debug
  -s                     Alias for --strip-all

The x86_64 Windows archive is .zip.

Try to suppress 10,000 lines of output. It printed a line for each
extracted file.

dumpbin probably exists somewhere on the runner, but it wasn't found.

Rather than from x86_64 windows, which seemed to produce an x86_64
executable:

    $ llvm-readobj configlet.exe
    File: configlet.exe
    Format: COFF-x86-64
    Arch: x86_64
    AddressSize: 64bit

despite compiling with:

    --cpu:arm64 --os:windows -d:zig -d:target:aarch64-windows-gnu

When cross-compiling from Linux to Windows:

- output the executable with a `.exe` file extension, by passing -o to
  Nim

- fix error for `llvm-readobj` not found

…to Windows"

This reverts commit 92a278d.

Nim gets passed

    -o:/home/runner/work/configlet/configlet/configlet

which overwrites the given

    -o:configlet.exe

Decrease the diff size of the current PR.

This won't do anything currently, since we don't do any cross-compiling
on a machine where llvm-strip is available.

Make it work on Linux, macOS, and Windows.

This reverts commit 8318c80.

Do this in a follow-up PR.

Not used for now. Reduce the PR diff size.