o Enhance dependency loop logging: print full chain instead of the
last link competing the loop;
o Add -g option to generate dependency graph suitable for GraphViz
visualization, loops and other graph generation issues are highlighted
automatically;
o Add -p option that enables grouping items that can be processed in
parallel.
Submitted by: Boris Lytochkin <lytboris at gmail>
Reviewed by: melifaro
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D25389
30fe2bbfae