Migrating from using the 'glpk-cut-log' repo to using an official GPLK release +...

Migrating from using the 'glpk-cut-log' repo to using an official GPLK release + a set of patches (#4775)

This PR attempts to migrate from @timothy-king's repo for glpk-cut-log to using a set of patches against the official release that 'glpk-cut-log' was based off of (4.52).

This is in preparation of trying to rework these patches to be against the latest GPLK release (4.65). If we can do this, then it makes it easier for CVC4's dependancy on GPLK to be able to follow upstream (rather than being stuck on a release that is 6.5 years old!).

I have added GPLK as an option for CI, but I do not know if we actually want this. My concern with adding this to CI is that we're then not testing non-GPL builds, which doesn't seem ideal.

However, before starting to rework the patches to be against 4.65, I want to make sure that things are actually working/stable against 4.52; so having at least one CI target that does use GPLK would be great.

Signed-off-by: Andrew V. Jones andrew.jones@vector.com