Simplify a bit, no functionnal change

Probably fix makesum and checksum

I may have "fixed" makesum, but maybe not, and I do not seem to find a port to test things.

makesum will need a re-design, thinking about it.

I refactored the 3 targets that had the exact same content. It's missing makesum, which will have the same problem.

As a proof of concept, I only changed the DISTFILES part of do-fetch.

Maybe using \0 instead of \n is better there, and juggling with IFS to split on \0, in case some distfile has a strange file name.

I'm not sure this would fix the command line length, it it just moves the length around.
I've been thinking of a real fix for this, and I think it needs to put it all in a temporary file, kinda

In D56578#1295345, @arrowd wrote:

I don't think removing entries without checking how long they have been unused is a good idea,

And how long an entry should be unused to make viable for deletion? I doubt we have a policy for that.

I don't think removing entries without checking how long they have been unused is a good idea,

Well, like everything committer related, it's in the committer's guide https://docs.freebsd.org/en/articles/committers-guide/#ports-exp-run, but I don't see what would break with this change.

I don't think this should break too many things.