Opaque lockRes.

Lemma store_compatible:
forall tpf mf pmap chunk b ofs v mf' (Hlt: permMapLt pmap (getMaxPerm mf))
(Hcomp: mem_compatible tpf mf)
(Hstore: Mem.store chunk (restrPermMap Hlt) b ofs v = Some mf'),
mem_compatible tpf mf'.