What I use for the Debian builds is: --prefix=/opt/trinity --includedir=/opt/trinity/include/kde --mandir=/opt/trinity/share/man --infodir=/opt/trinity/share/info --with-extra-libs=/opt/trinity/lib --sysconfdir=/etc --localstatedir=/var --libexecdir="${prefix}/lib/kdebase-kde3" --disable-rpath --with-xinerama --enable-closure (when needed, which is most of the
time)
CORRECTION: --libexecdir="${prefix}/lib/kdebase-kde3" is module specific and should probably be omitted.
How do I learn the defaults if any of those variables are not explicitly declared?