document required fonts for FreeBSD

[clive]

After installation, I would often get the following error message on my FreeBSD system:

Graphviz macro processor has detected an error. Please fix the problem before continuing. 
The command
   "/usr/local/bin/dot"  -Tpng -o/home/usrsrc/trac/projects/newt/graphviz/a6f4d11bdd9c39f2f8ecdddfec321b0bfd3bcb92.dot.png
failed with the the following output:

Error: fontconfig: Couldn't retrieve font family name. : Times-Roman

This is because graphviz requires by default some fonts which for which the installation is not automatically triggered.

Even running dot from the command-line will trigger this error message:

% dot -Tpng -o ~/public_html/t.png test.dot
Error: fontconfig: Couldn't retrieve font family name. : Times-Roman

You may wish to make a note somewhere in the GraphvizPlugin documentation that if FreeBSD users encounter this error they should install the following package:

x11-fonts/urwfonts

Installing urwfonts, ​as suggested in the FreeBSD manual, fixes this problem completely.

[anonymous]

Fixed in changeset:1234.