Gentoo's Bugzilla –
Attachment 394854 Details for
Bug 533526sci-geosciences/mapnik-2.1.0 with dev-libs/boost-1.56.0-r1 - src/css_color_grammar.cpp:264:25: required from here: /usr/include/boost/utility/result_of.hpp:189:8: error: wrong number of template arguments (1, should be 4)