emacs-app-devel build fail on master not detected by buildbot

[Aaron Madlon-Kay]

For the general case an update to MacPorts base would be required, but
for the purposes of any given port shouldn't it be sufficient to do
`depends_fetch-append port:git`?

And my apologies; it wasn't you, Dan, who took the position I
described earlier, it was another commentator:
https://github.com/macports/macports-ports/pull/9295#discussion_r532780239

-Aaron