recode: 3.7-gitrev -> 3.7.4, new home (#68045)

* recode: pname-ify

* recode: 3.7-* -> 3.7.2, new home

gnu homepage still exists (for now),
but links to the github repo we switch to :).

* recode: use pre-generated tarball to avoid gen, fix

* recode: 3.7.2 -> 3.7.4

https://github.com/rrthomas/recode/blob/v3.7.4/NEWS
(3.7.3 notes as well)