Building a package needing the workdir of another package

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

What's the intended way of building a package that needs files from the working 
directory of the build of another package?

I'm trying to pkgsrc dovecot-managesieve. Building it needs files from a built 
dovecot because it links against libraries dovecot doesn't export.
Yes, best solution would be if dovecot did install those libraries, but I'm not 
in a position to tell dovecot's or managesieve's authors that should be done.

Solution 1: Use DISTFILES, CONFIGURE_DIRS and BUILD_DIRS to build dovecot (or 
at least, the relevant libraries) inside dovecot-managesieve's working 
directory. Should probably work, but duplicates both build time and pkgsrc 
configuration.

Solution 2: Don't build managesieve as a separate package, but as an option to 
the dovecot package. Should work too, but breaks modularity.