>  I have looked at your SlackBuild and I am building with:

Make sure you download the latest. The latest includes the changes 
discussed.

>  CFLAGS="${CFLAGS} -I/usr/include/tqt -I${TDEDIR}/include -
>I${QTDIR}/include
>-fpermissive" \
>  CXXFLAGS="${CXXFLAGS} -I/usr/include/tqt -I${TDEDIR}/include
>-I${QTDIR}/include -fpermissive" \
>  echo yes | python2 configure.py \
>    -d "${PY2LIB}/sip4_tqt" \
>    -y tqt-mt \
>    -v /usr/share/sip/tqt

I install sip4-tqt and python-tqt (and everything else except 
tqtinterface) to $PREFIX=/opt/trinity.

Rebuild sip4-tqt before rebuilding python-tqt.

My current python-tqt configuration:

if [ "$PREFIX" = "/usr" ]; then
  FLAGS="$CPUOPT -L${PREFIX}/lib${LIBDIRSUFFIX} -I/usr/include/tqt -
I/${QTDIR}/include -I${PREFIX}/include"
else
  FLAGS="$CPUOPT -L${PREFIX}/lib${LIBDIRSUFFIX} -I/usr/include/tqt -
I/${QTDIR}/include -I${PREFIX}/include -I/usr/include"
fi

echo "yes" | python configure.py \
  -b "${PREFIX}/bin" \
  -d "$PYTHONLIB/python_tqt" \
  -q "$PREFIX" \
  -y tqt-mt \
  -o /usr/lib${LIBDIRSUFFIX} \
  -v /usr/share/sip/tqt \
  -u \
  CFLAGS="$FLAGS" \
  CXXFLAGS="$FLAGS"

As I build to /opt/trinity, visually substitute /opt/trinity with 
$PREFIX and you'll see you are building to /usr (the old build 
script before the recent patches). The two package configurations 
have to be updated similarly otherwise python-tqt can't find sip4-
tqt files.

>  What has changed? This used to build flawlessly?

The two packages are now built as modules and a presumption with 
that is the two packages no longer conflict with upstream distro 
packages. Thus, /opt/trinity/bin/sip no longer overwrites the 
distro /usr/bin/sip. Likewise with python-tqt. The module portions 
of the packages do not overwrite anything because they are 
installed to their own subdirectories.

A side comment: why are you using -fpermissive? I don't use that in 
any build scripts.

Darrell