Rewrite buildsystem to use Makefile.gappkg

[fingolfin]

This should remove the problems on OpenBSD (see issue #562, CC @dimpase), and speed up build times.

I have done some limited testing on macOS and Linux. Before I spend more time on polish, I'll wait to hear if there is any interest in this (plus CI results will of course be interesting).

[fingolfin]

The test failure seems spurious (failed to clone the repo?). I'll wait for PR #567 to be merged, then will rebase, and we'll see how the tests fare then -- also those done against conda

[fingolfin]

Good that the azure tests run again, they immediately discovered a problem (cannot find install-sh, install.sh, or shtool). I've seen this before and will try to fix it.

[dimpase]

Thanks! I'll test on OpenBSD and report.

[james-d-mitchell]

Just to say that @fingolfin and I discussed this today, and I'll be happy to merge this when you tell me you're done @fingolfin. Many thanks!

[dimpase]

should this be tested on GAP master, or on another branch?

[fingolfin]

@dimpase whichever is handy for you (and of course the OpenBSD problem should manifest, I don't know whether you tested this with multiple GAP versions)

[fingolfin]

@james-d-mitchell from my POV this is done but perhaps we wait and see what @dimpase reports?

[dimpase]

This allows one to build working Digraphs (DigraphsTestAll() passed). Now, the same dylib build problem with Semigroups. Opening an issue there.

[fingolfin]

@dimpase out of curiosity, what does file bin/*/digraphs.so say with this PR versus with main?

[james-d-mitchell]

Excellent thanks very much @fingolfin ! I'll wait to hear the last word from @dimpase, then merge

[dimpase]

@dimpase out of curiosity, what does file bin/*/digraphs.so say with this PR versus with main?

it says ELF 64-bit LSB shared object, x86-64, version 1 (same as for broken semigroups.so)
More interesting is what ldd says:

$ ldd bin/x86_64-unknown-openbsd7.1-default64-kv8/digraphs.so  
bin/x86_64-unknown-openbsd7.1-default64-kv8/digraphs.so:
        Start            End              Type  Open Ref GrpRef Name
        000001b09ef72000 000001b09f005000 dlib  2    0   0      /home/dima/tmp/gap/pkg/digraphs/bin/x86_64-unknown-openbsd7.1-default64-kv8/digraphs.so
        000001b060da8000 000001b060e8c000 rlib  0    1   0      /usr/lib/libc++.so.9.0
        000001b02581b000 000001b025861000 rlib  0    2   0      /usr/lib/libc++abi.so.6.0
        000001b057206000 000001b057212000 rlib  0    1   0      /usr/lib/libpthread.so.26.1

whereas for semigroups.so it's an error:

$ ldd bin/x86_64-unknown-openbsd7.1-default64-kv8/semigroups.so                                                                                      
bin/x86_64-unknown-openbsd7.1-default64-kv8/semigroups.so:
Cannot load specified object
bin/x86_64-unknown-openbsd7.1-default64-kv8/semigroups.so: exit status 1
$ file bin/x86_64-unknown-openbsd7.1-default64-kv8/semigroups.so 
bin/x86_64-unknown-openbsd7.1-default64-kv8/semigroups.so: ELF 64-bit LSB shared object, x86-64, version 1

without this PR ldd was failing on digraphs.so

[dimpase]

Excellent thanks very much @fingolfin ! I'll wait to hear the last word from @dimpase, then merge

it's a big OK from me.