XFree86-3.3 imake config files can't handle IncSubDir having more than
one component ("X11/Xaw3d" in this case), so work around it by
explicitly creating a symlink tree from post-extract (ugh).
% patch-ab is not necessary anymore because the bug is now fixed in
. the original source.
% post-configure (which was doing "make includes") is not necessary
. because xmkmf is now called with "-a". (Yeah, should have redefined
. XMKMF in Makefile in the first place....)
