Improve documentation for libpotrace / scour requirements / possible other optional dependencies

[Hachmann]

Currently, in README or INSTALL files, there is no mention of these two outside libraries.

While Scour can still be added after compiling, and there's a good warning message about the issue if it's missing, libpotrace is a relevant dependency for compiling already - if missing, important tools won't work.

The only place where a person who compiles Inkscape may encounter a warning about libpotrace is somewhere in the long stream of messages one gets when preparing for compiling. It's easy to overlook it there.

Could the optional dependencies please be documented (aside from the release notes for 0.92):

here:
http://wiki.inkscape.org/wiki/index.php/Tracking_Dependencies#Libs

and in the INSTALL / README file, whichever is preferred/more up-to-date ?

(Judging from a message to the forum, the packagers for Chakra Linux may have overlooked it, just like I forgot to check if it's installed, and like it was first missing from the new Homebrew formula.)

[Hachmann (marenhachmann)]

Btw. what's the reason for libpotrace not being a hard dependency? We do 'advertise' the trace bitmap feature.

[Alex Valavanis (valavanisalex)]

Re Comment #1 - mostly because Inkscape *can* still be used without Potrace. I guess it's feasible that some platforms may not have a convenient Potrace package available, so adding a hard dep would make life difficult for those users/maintainers.

[Hachmann (marenhachmann)]

Thanks, @Alex!

[Hachmann (marenhachmann)]

Tried to add optional dependencies, hope they can be useful for someone.

[Hachmann (marenhachmann)]

http://wiki.inkscape.org/wiki/index.php?title=Tracking_Dependencies&oldid=108381