debug - Enable extra debug codepaths, like asserts and extra output. If you want to get meaningful backtraces see https://wiki.gentoo.org/wiki/Project:Quality_Assurance/Backtraces
fortran - Build FortranProject plugin which enables to use Code::Blocks IDE for Fortran language
pch - Enable precompiled header support for faster compilation at the expense of disk space and memory (>=sys-devel/gcc-3.4 only)
