gcc: cherry picked patch for support of current CLooG

* cloog now uses CLOOG_LANGUAGE_C instead of LANGUAGE_C.
* graphite-clast-to-gimple.c (CLOOG_LANGUAGE_C): Provide if missing.
        (set_cloog_options): Use it.
imported PPL 0.11.1 and CLooG 0.18.0.

* these are dependencies for gcc 4 Graphite engine build.
* CLooG 0.18.0 includes ISL 0.11.1 which is the backend that the build script enables.
* PPL is needed by GCC build even if it isn't the chosen backend.