Created attachment 285509 [details] patch to ebuild The Python files installed with USE="wxwidgets" in /usr/lib64/grass64/etc/wxpython are compiled by grass's own build system. Attached patches get portage to do the job for me.
Created attachment 285511 [details, diff] patch to grass
Created attachment 285541 [details, diff] patch to ebuild Compile the grass Python module too.