CI is failing: somehow pmbootstrap thinks ktp-common-internals provides make?!

If you came here, because of a pmbootstrap error message, read pmbootstrap#1969.

Original issue text:

CI is failing in !13 (merged). When looking at the log of the local service in the artifacts, or when running CI locally from master and looking at the local service log there, it fails with:

(005690) [16:11:03] (native) calculate depends of abuild, build-base, ccache, git (pmbootstrap -v for details)
(005690) [16:11:04] libc-dev: guessed to be a subpackage of libc, which we can't find in pmaports, so it's probably in Alpine
(005690) [16:11:04] musl-dev: guessed to be a subpackage of musl, which we can't find in pmaports, so it's probably in Alpine
(005690) [16:11:04] (native) install abuild build-base ccache git
(005690) [16:11:04] ERROR: 'NoneType' object is not subscriptable
(005690) [16:11:04] See also: <https://postmarketos.org/troubleshooting>
(005690) [16:11:04] Traceback (most recent call last):
  File "/builds/postmarketOS/build.postmarketos.org/_temp/local_job/pmbootstrap/pmb/__init__.py", line 63, in main
    getattr(frontend, args.action)(args)
  File "/builds/postmarketOS/build.postmarketos.org/_temp/local_job/pmbootstrap/pmb/helpers/frontend.py", line 109, in build
    args.strict, src=src):
  File "/builds/postmarketOS/build.postmarketos.org/_temp/local_job/pmbootstrap/pmb/build/_package.py", line 513, in package
    skip_init_buildenv, src):
  File "/builds/postmarketOS/build.postmarketos.org/_temp/local_job/pmbootstrap/pmb/build/_package.py", line 219, in init_buildenv
    pmb.build.init(args, suffix)
  File "/builds/postmarketOS/build.postmarketos.org/_temp/local_job/pmbootstrap/pmb/build/init.py", line 38, in init
    build=False)
  File "/builds/postmarketOS/build.postmarketos.org/_temp/local_job/pmbootstrap/pmb/chroot/apk.py", line 222, in install
    suffix, arch)
  File "/builds/postmarketOS/build.postmarketos.org/_temp/local_job/pmbootstrap/pmb/chroot/apk.py", line 174, in replace_aports_packages_with_path
    package + "-" + data_repo["version"] + ".apk")
TypeError: 'NoneType' object is not subscriptable

I've added debug prints. The "package" where it fails is ktp-common-internals, which was recently added/changed in pmaports.git.

I ran the same pmbootstrap command with -v, and it says:

(005964) [00:01:11] make: provided by: ktp-common-internals-19.08.2-r1 in /home/user/.local/var/pmbootstrap/cache_git/pmaports/kde/ktp-common-internals

Seems like a bug in pmbootstrap - why would it provide make?! Investigating ...