CI doesn't build ports in dependency order

[barracuda156]

Either ​this or neighboring ones. We got all sorts of random failures for existing ports which built fine earlier and still build fine locally (not just for me, but for others too).

So far it is either alleged dependency cycle (which may involve test dependencies which are now, apparently, confused for build/lib dependencies) or activation failure.

Activating all dependencies...
invalid command name ""
    while executing
"$workername eval {validate_macportsuser}"
    (procedure "mportexec" line 5)
    invoked from within
"mportexec $ditem activate"
Error: Activate failed: invalid command name ""
Activation of dependency 'gcc12-libcxx' with variants '+clang14' failed, aborting.
Processing dependencies for 'R-ic.infer' failed, aborting.

Error: The following dependencies were not installed because all of them have unmet dependencies (likely due to a dependency cycle): libiconv
Build of dependency 'libtextstyle' with variants '' failed, aborting.

Multiple examples here: ​https://github.com/macports/macports-ports/pull/20736 (where ports which are known to build fine, now failed on CI) Likely related too: ​https://github.com/macports/macports-ports/pull/20702 (this one involves changes to R PG, so may or may not be caused by mpbb, but I think it is)

[barracuda156]

From another PR:

Error: The following dependencies were not installed because all of them have unmet dependencies (likely due to a dependency cycle): R-Hmisc R-data.table
Build of dependency 'R-qgraph' with variants '+gcc12' failed, aborting.
Processing dependencies for 'R-IsingFit' failed, aborting.

--->  Dependencies to be installed: R-memisc R-data.table
Error: The following dependencies were not installed because all of them have unmet dependencies (likely due to a dependency cycle): R-memisc
Build of dependency 'R-mclogit' with variants '' failed, aborting.
Processing dependencies for 'R-abn' failed, aborting.

Needless to say, everything worked fine earlier with all these.

[jmroot (Joshua Root)]

While there was an issue with mpbb, it only affected what is supposed to be a very rare case: when a dependency of the port being built has not itself been built yet. It only caused noticeable problems because the CI script appears to be simply building changed ports in the order they appear in the git diff, rather than in dependency order.

[jmroot (Joshua Root)]

In a789b83fb668c3bd4ad8a3cfde8f8450e6dcec4a/macports-ports (master):

GitHub Actions: list subports in dependency order

Closes: #68408