Log Message:
lasso: fix the build with inkscape installed

Basically lasso installs additional files when Inkscape is available,
which it would normally re-generate but are already in the source tree.

This unconditionally caches "/bin/false" as the path to Inkscape, which:

* will always behave the same (install the missing files)
* will break if they ever have to be re-generated (thus exposing the
  issue directly, which is a good thing)

In addition since lasso can provide additional documentation when
gtk-doc is installed, I have enabled this by default as well.

Bumps PKGREVISION.

Reviewed by manu@, thanks!