nodes a la Appel and George.
Maps: in PTree.combine, compress useless subtrees.
Lattice: more efficient implementation of LPMap.
Makefile: build profiling version


git-svn-id: https://yquem.inria.fr/compcert/svn/compcert/trunk@1139 fca1b0fc-160b-0410-b1d3-a4f43f01ea2e