Link a dependency in Synaptic to the one already installed from source

Question

I want to install SVN version of Quantum GIS and already I have a SVN version of GRASS GIS. As instructed in QGIS Wiki here, I added the qgis repository to my sources.list file. Now I am able to see qgis1.8.0svn version in Synaptic but when I try to install it, GRASS is a dependency(older version is available in the repository and even if I add Ubuntu GIS Unstable PPA it's not the developmental version available there, i.e., version 6.5 is not available; which offers nice features). GRASS's SVN version does not show up in Synaptic as we don't add URL to sources.list. It has to be done through svn checkout. How can I set Synaptic to identify the already installed GRASS GIS in my /usr/local/ directory?

Answer 1

This is customarily done by using equivs - creating a trivial package. You create a package whose sole purpose is (in this case) is to tell the package management system that you already have GRASS GIS installed. In your case the package would have no content, just dependency information.

See equivs Ubuntu package page, equivs-build Ubuntu man page, and a random Ubuntu howto, Howto: create "configuration packages" with equivs. For the record, this idea originated in Debian.