net-analyzer/ntop (at least 4.0.3) needs dev-python/mako to support some functions, like map display. there is no mako useflag and its not a dependency.
Created attachment 307789 [details, diff] ebuild patch archtester ntop # grep -r mako /mnt/gen2/TmpDir/portage/net-analyzer/ntop-4.1.0/work/ntop-4.1.0/ from mako.template import Template from mako.lookup import TemplateLookup et al. archtester net-analyzer # qlist mako | grep lookup /usr/lib64/python2.7/site-packages/mako/lookup.py /usr/lib64/pypy1.8/site-packages/mako/lookup.py Decided against making a new mako USE flag.
+ 13 Dec 2012; Sergey Popov <pinkbyte@gentoo.org> ntop-4.1.0.ebuild: + Add dev-python/mako to runtime deps, wrt bug #410255 Fixed in 4.1.0