Add build testing for more platforms about argp-standalone

[wdlkmpx]

I verified that the lib also compiles for Haiku (cross-compiler)

If it supports MSVC, it's quite portable, all the other compilers are basically GCC with some posix compatibility layer in the headers/libs, so whatever uses GCC already contains some limited POSIX stuff and perhapps full C99/C11 support

These are exotic compilers (except mingw) that you will not find on any public CI service

For mingw-w64 i686, I once used AppVeyor. Github might also include it somewhere

[wdlkmpx]

I used to have an AmigaOS cross-compiler, but it's a mess, I deleted it. I might try to add it again

If you know any other simple libs or apps that you want to know if it compiles for djgpp or haiku, @ mention me in a commit or issue, and I will test it and reply

[guijan]

It's better to automate this stuff. It's probably possible to automate compiling DJGPP if there is no install or we change some variables with the GCC/binutils/DJGPP versions, then the binaries can be saved in persistent github storage and reused for subsequent runs. It may even be possible to write a shell script to use as Meson's exe_wrapper which runs tests under some sort of DOS environment like FreeDOS or DOSBox.

I don't really know how to do this though.

[wdlkmpx]

The best way to address this is by using custom docker images, docker images you build with apps you want to include. You have to upload them to dockerhub... there may be a docker image ready @ dockerhub

I've created and used docker images with Gitlab CI, Cirrus CI and Circle CI. Circle CI provides some really advanced usage, but it's more complex

Overall, it may be too much for such a small project. I've figure out that sometimes one acquires so much knowledge, and it end it doesn't even matter, it all was for nothing