message: add clean emp option
diff: @@ -63,7 +63,7 @@ obj/mid_layer/%.o: src/mid_layer/%.cpp
  tests:: all
  $(Program)
  -compile-emp:prepare-emp compile-emp-tool compile-emp-ot compile-emp-m2pc compile-emp-sh2pc
  +compile-emp:prepare-emp compile-emp-tool compile-emp-ot compile-emp-m2pc
  prepare-emp:
  @mkdir -p $(builddir)/EMP
  @@ -73,21 +73,19 @@ compile-emp-tool:
  @cd $(builddir)/EMP/emp-tool
  @cmake CMakeLists.txt
  @make -f Makefile
  + @touch compile-emp-tool
  compile-emp-ot:
  @cd $(builddir)/EMP/emp-ot
  @cmake CMakeLists.txt
  @make -f Makefile
  + @touch compile-emp-ot
  compile-emp-m2pc:
  @cd $(builddir)/EMP/emp-m2pc
  @cmake CMakeLists.txt
  @make -f Makefile
  -
  -compile-emp-sh2pc:
  - @cd $(builddir)/EMP/emp-sh2pc
  - @cmake CMakeLists.txt
  - @make -f Makefile
  + @touch compile-emp-m2pc
  compile-blake:
  @echo "Compiling the BLAKE2 library"
  @@ -188,6 +186,11 @@ clean-blake:
  @rm -rf $(builddir)/BLAKE2
  @rm -f compile-blake
  +clean-blake:
  + @echo "Cleaning EMP library"
  + @rm -rf $(builddir)/EMP
  + @rm -f compile-emp-tool compile-emp-ot compile-emp-m2pc
  +
  clean-cpp:
  @echo "cleaning .obj files"
  @rm -rf $(OUT_DIR)
  