The master branch contains mlton-parmem. To compile the old mlton-spoonhower, build the legacy/mlton-spoonhower branch

From scractch, just type make all-no-docs to build the compiler. The compiler will then be located in build/bin/mlton-parmem. Note that you cannot use a -j argument to parallelize compilation as the Makefile does not support this.

If you just modified the runtime, recompile it alone with make runtime. You can use a -j argument for runtime compilation only.

If you just modified the basis or schedulers, recompile them (really, just reinstall them in the build directory) alone with make basis.