Currently, HAVE_GCC=4 and HAVE_GDB=6 will generate extra files from the
ones currently in src/disrib/sets/. gcc4 is handling them by having extra
logic stuck in sets.subr to include any appropriate .ad file; gdb6 is
currently not handling it at all (i.e. flist breaks). And then there's
x11_version, which does an entirely different set of things.

Would the right thing to do in these cases be to automagically transform
HAVE_FOO=37 into havefoo37 attributes/variables in sets.subr and in the
setlists themselves? thus, lists/comp/.mi could have

./usr/bin/gdbtui	comp-debug-bin	gdb havegdb6

and the files in lists/base/gcc4.mi, et al, could be moved into the
appropriate mi, md, or ad flist?