The new DIST_TUPLE syntax is still undergoing some minor/major
tweaks (stay tuned).
As for retiring the old MASTER_SITES syntax, I acknowledge that having
all the stuff in DISTFILES was handy for EXTRACT_ONLY=<empty> ports.
But the rewriting stuff as in dest{url}sufx already made that cumbersome.
So I exposed some more internals:
ALL_DISTFILES contains the list of all distfiles destinations (as cobbled
from DISTFILES* after url -> dest substitutions.
likewise for ALL_PATCHFILES.
I could also expose ALL_SUPDISTFILES, but I expect the 3rd one to be
thoroughly unneeded by anyone.
(note: this doesn't cost anything, portswise, as these variables were
already computed as _LIST_DISTFILES/_LIST_PATCHFILES, and adding a new
name for them doesn't trigger a value copy until the variable gets
actually used)
