Add preliminary version of our second lock point-analysis (SLPs), by building on top of Kalmer's MayLocksets.

The domain is the same, just the transfer functions are different: by default we propagate the
empty set, and only record locks if we already have at least one. (Hence the "depends" line upon
registering the MCP with Goblint). Note that the analysis info is
being attached to the subsequent node, not the actual lock statement (ick)!

Due to the semantics of pthreads, at the moment we don't consider recursive locks.

Sample invocation:

goblint --set ana.activated "[['base', 'maylocks','thread-id-location','slps']]" --sets result indented knot_comb-3.c >out.xml