mpbb-install-port should use --unrequested

[ryandesign (Ryan Carsten Schmidt)]

mpbb-install-dependencies runs port install with --unrequested but mpbb-install-port doesn't. This results in some ports being installed requested, and others not, depending on the order in which the builds were run.

For example, on an empty worker, if we build zlib and then libpng (which depends on zlib), the first build would mark zlib requested and the second would mark libpng requested (and would not change zlib because it is already installed), while doing it in the other order would first mark zlib unrequested and libpng requested, and the second build would not change the marking of zlib because it is already installed.

Depending on the worker, 72-83% of ports installed are marked requested while the remainder are marked unrequested. Is this distinction supposed to be useful for something? It doesn't seem useful to me, and I suggest all ports should be marked the same way. Marking all ports as unrequested would have the advantage that port leaves could be used to identify ports not being used by other installed ports, which could then be uninstalled if the second suggestion from #57464 (have mpbb uninstall a port if nothing depends on it) is implemented.

[ryandesign (Ryan Carsten Schmidt)]

​https://github.com/macports/mpbb/pull/11

[Ryan Schmidt <git@…>]

In f114e42daf9d9a263ee4cdb7555dc7c4a623755b/mpbb (master):

Set unrequested flag when installing ports

We already install dependencies with the unrequested flag. This now also
installs the main port that way. There seems to be no reason to make a
distinction between the main port and its dependencies with regard to
this flag, since the idea is for all of the ports (or at least, all of
the ports that are dependencies of another port) to remain installed,
regardless of whether they were originally installed explicitly or as a dependency.

Closes: #57571