Add Windows CI to our GitHub build workflow

[tsjensen]

Just a reminder to investigate if and how checking on Windows MinGW can be added to the workflow.

Some links:

• https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners/about-github-hosted-runners#supported-runners-and-hardware-resources
• https://github.com/marketplace/actions/install-mingw
• https://docs.github.com/en/billing/managing-billing-for-github-actions/about-billing-for-github-actions#minute-multipliers

[mathomp4]

I suppose one could also use WSL via:

https://github.com/marketplace/actions/setup-wsl

or what I'm sure are several other ways...

[tsjensen]

Also:

• https://github.com/jqlang/jq/blob/master/.github/workflows/ci.yml#L190

[tsjensen]

So, I have tried adding Windows CI, but I am stuck. My current try is on the windows-ci branch (CI job). We use MINGW32 because that's how we've always done it, but I would be open to different platforms as long as the result is a stand-alone Windows binary that does not require extra libs or runtime.

Status:

• I can install all the dependencies.
• The code does not compile:
  • Including sys/stat.h leads to error: #error unimplemented for this target. Tried to remedy via undefining _POSIX_TIMERS but to no avail.
  • strdup() is not defined. Tried to remedy via __MISC_VISIBLE but to no avail.
  • ... you'll find more problems for sure.

I am currently out of ideas on how to make this work.

Any help would be much appreciated!