Gentoo's Bugzilla –
Attachment 521000 Details for
Bug 648764media-gfx/graphviz-2.40.1-r1 : /.../c++<snip>_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler op