Even with USE="-arts", koctave seems to need arts, yet doesn't depend on it: checking for KDE... libraries /usr/kde/3.4/lib, headers /usr/kde/3.4/include checking for KDE paths... defaults checking for dcopidl... /usr/kde/3.4/bin/dcopidl checking for dcopidl2cpp... /usr/kde/3.4/bin/dcopidl2cpp checking for mcopidl... not found configure: error: The important program mcopidl was not found! Please check whether you installed aRts correctly. !!! ERROR: sci-mathematics/koctave-0.65 failed. !!! Function kde_src_compile, Line 141, Exitcode 1 !!! died running ./configure, kde_src_compile:configure !!! If you need support, post the topmost build error, NOT this status message.
Added a configure patch to allow compilation without arts. Please sync up in about an hour and it should work.