Add missing dependencies.

* USES=pkgconfig was missing so exiv2 detection was broken, for example.
* USE_QT5=declarative and USE_QT5=printsupport were missing, and the latter
  is required for the port to build correctly with the upcoming Qt 5.3.2.
  I've added an upstream commit to properly detect and use PrintSupport in
  the build process as well.

PR:		194596
Approved by:	Hannes Hauswedell <h2+fbsdports@fsfe.org> (maintainer)


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@371492 35697150-7ecd-e111-bb59-0022644237b5