emerging xorg 7.0 from 6.8.2 After many iterations, the following files end up not found: keysymdef.h (package xproto) XKBlibinit.h (package kbproto) X11/Xauth.h (package libXau) X11/Xdmcp.h (package libXdmcp) I think these are files whose ownership changed during the changeover from 6.8.2 to 7.x, and so uninstalling 6.8.2 killed them (that's a guess). Re-emerging the four packages above (I also re-emerged xf86bigfontsproto, bigreqsproto and xcmiscproto for good measure) solved the problem, but it wasn't pretty. The ebuild should see to it that all the necessary files are present, and their packages rebuilt if necessary.
Reopen with ebuild name, version, exact error messages and emerge --info.