makefile adjusted becaus clean was not removing all the executables
makefile adjusted becaus clean was not removing all the executables

rbaghdadi/pencil-benchmark,pencil-language/pencil-benchmark,pencil-language/pencil-benchmark,dividiti/pencil-benchmark,rbaghdadi/pencil-benchmark,dividiti/pencil-benchmark,rbaghdadi/pencil-benchmark,pencil-language/pencil-benchmark,dividiti/pencil-benchmark