app-admin/otpcalc contains virtual/x11 in DEPEND. "included-headers.sh" and "linking_libs.sh" report no X dependencies at all. So I double checked, and in fact, all required X libraries are dependencies of gtk+ (and are linked via `gtk-config --libs` in the linker command line). So I conclude that virtual/x11 may simply be removed.
Thanks for the report, fixed in cvs