Compilation error with UG_ENABLE_DEBUGGING=ON

Enabling UG_ENABLE_DEBUGGING=ON in cmake configuration results in compilation errors:

• dune-uggrid/low/debug.h:175:1: error: ‘INT’ does not name a type
• dune-uggrid/parallel/initparallel.cc:98:52: error: ‘me’ was not declared in this scope
• dune-uggrid/parallel/initparallel.cc:135:52: error: ‘me’ was not declared in this scope

Tested current git version c21ae1b3 with gcc-6.3. All configuration is default, build with

dune-common/bin/dunecontrol --builddir=build all

then setting the cmake option in dune-uggrid/build/CMakeLists.txt and recompile dune-uggrid.