Makefiles created with mkfmf do not clean out .mod files

[hkershaw-brown]

The makefiles created with mkmf do not clean out .mod files

make clean

leaves a bunch of *.mod files.

In mkmf,

-print MAKEFILE "clean: neat\n\t-rm -f .cppdefs \$(OBJ) $opt_p\n";
print MAKEFILE "clean: neat\n\t-rm -f .cppdefs *.mod \$(OBJ) $opt_p\n";

Or something a bit cleverer, e.g. only deleting .mods created when running make (for that Makefile). I'm not sure whether this is a good idea, it's probably best to just blast *.mod.

Note quickdbuild.sh cleans out *.mod

side note: submodules are *.smod

[hkershaw-brown]

fixed in #468