To compile wxGTK with gtk2 you have to disable odbc. So the use gtk2 should be changed to this: use gtk2 && myconf="${myconf} --enable-gtk2 --enable-unicode --without-odbc
I have updated wxGTK-2.4.0 in portage. I modified odbc detection so if both odbc and gtk2 are in use, emerge spits info letting the user know about the incompatibility. gtk2 is chosen by default.