When updating such a package or modifying Makefile.common, one has to
search the whole pkgsrc tree for files that use the Makefile.common, and
in some cases this cannot be guessed by the package names alone. For
example, x11/labltk/Makefile uses lang/ocaml/Makefile.common, which was
a little surprise for me, because the former doesn't have a name related
to OCaml.
Therefore, I wrote a bit of code that prints the following warning:
$ pkglint -e x11/labltk
WARN: x11/labltk/../../lang/ocaml/Makefile.common:3: \
Please add a line "# used by x11/labltk/Makefile" here.
Since Makefile.common files usually don't have any comments and
therefore not a clearly defined interface, they should at least
contain references to all files that include them, so that it is
easier to see what effects future changes may have.
If there are more than five packages that use a Makefile.common,
you should think about giving it a proper name (maybe plugin.mk)
and documenting its interface.
Do you find this warning useful? Unnecessary? Whatever?