Update CI integration, switch Cygwin tests to GH Actions

[fingolfin]

Please DO NOT MERGE until I've verified it all works as expected

[lhsoicher]

@fingolfin Please let me know if/when I can merge this PR. Thanks.

[fingolfin]

Strange, it dies with error

+ ./configure /home/runneradmin/gap
./configure: line 4: /home/runneradmin/gap/sysinfo.gap

inside of gap-actions/build-pkg@cygwin-v1; yet in the preceding gap-actions/setup-gap@cygwin-v2 that file existed and seemingly worked fine:

  ==== Checking profiling
  Running './configure' '/home/runneradmin/gap' 
  Using settings from /home/runneradmin/gap/sysinfo.gap
  Running 'gmake' 'clean' 
  rm -rf bin/x86_64-pc-cygwin-default64-kv8 gen
  Running './configure' '/home/runneradmin/gap' 
  Using settings from /home/runneradmin/gap/sysinfo.gap
  Running 'gmake' 
     GAC     src/profiling.cc => gen/src/profiling.o
     GAC     src/md5.cc => gen/src/md5.o
     GAC     gen/src/profiling.o => bin/x86_64-pc-cygwin-default64-kv8/profiling.so

@ChrisJefferson @wilfwilson any idea what might be causing this?

[wilfwilson]

I'm really not sure @fingolfin, sorry.

[fingolfin]

This is really strange, considering that I copied the CI setup basically verbatim from datastructures and io, where it works smoothly.

Perhaps this requires using tmate to log into the GH action CI job and investigate more closely. I'll try and see if I can do that (if nobody beats me to it) later today, but now I need to prepare for my lecture

[ChrisJefferson]

I will have a quick look now

[ChrisJefferson]

One issue is you've changed the configure script to use source instead of ., but the script is hard-wired to /bin/sh, which doesn't (have to) support source if it isn't actually bash.

[fingolfin]

Problem was caused by linenedings. Chris fixed it by adding a .gitatributes file.