JDBetteridge/pip install

[JDBetteridge]

Make libsupermesh pip installable

[connorjward]

This is not yet ready for merge as it does not work on Macs. In particular it is not producing a viable .dylib that Firedrake can link to in setup.py. I think the solution is something to do with the CMake suffix (see here about sysconfig.get_config_var("SO")) but until I have access to a Mac to develop on this can't go anywhere.

Once this has been fixed the changes that were reverted here may be restored.

[connorjward]

# libsupermesh
# example:
# gcc -I/supermesh/include
# gcc /supermesh/supermesh.cpython-311-x86_64-linux-gnu.so \
#    -l:supermesh.cpython-311-x86_64-linux-gnu.so \
#    -Wl,-rpath,$ORIGIN/../../supermesh
supermesh_dir = Path(supermesh.__path__._path[0]).absolute()
supermesh_so = next(supermesh_dir.glob('*.so'))
supermesh_ = ExternalDependency(
    libraries=[f":{supermesh_so.name!s}"],
    include_dirs=[str(supermesh_dir.joinpath("include"))],
    library_dirs=[str(supermesh_dir)],
    runtime_library_dirs=[os.path.join(site.getsitepackages()[0], "supermesh")]

since it got lost...