this is a dup of bug 142719 which I unfortunately can not reopen as it is NOT fixed. media-gfx/graphviz is still listed as RDEPEND Reproducible: Always Expected Results: DEPEND="doc? ( media-gfx/graphviz )
Thanks, this is fixed in 1.2.4 As log4c does not appear to use it directly, I dropped the dep completely in favour of enforcing a USE dep of doxygen[dot].