Porting FLASH to new architectures should be fairly straightforward for most Unix or Unix-like systems. For systems which look nothing like Unix or which have no ability to interpret the setup script or makefiles, extensive reworking of the meta-code which configures and builds FLASH would be necessary. We do not treat such systems here; rather than do so, it would be simpler for us to do the port ourselves.
For Unix-like systems, you should make sure that your system has csh, a gmake that permits included makefiles, awk, sed, and Python. Next, create a directory in sites/ with the name of your site. It is best to name your site according to the output from the hostname -f command (it will return something like code.rochester.edu) so that the setup script can automatically determine your site without you needing to manually specify the -site setup script option. Copy a Makefile.h from a pre-existing site directory into your new site directory.