> The problem that I've found when I was trying to port my installer to FreeBSD was their make doesn't like GNU Makefiles. Not sure when they diverged from one another so having Make everywhere, doesn't necessary mean your Makefile will work everywhere.

As with many other utilities, you can always run "gmake" for GNU make. If you can get what you need to do done with portable make, by all means do so, but if you need to depend on GNU make, it's widely available.