configure error

[Angus Leeming]

using configure --with-frontend=kde
configuration falls over if QT or KDE aren't installed in certain hardwired
locations. This is daft, since two shell variables are defined when running KDE
but not employed by the configure script.

Why not test 
$KDEDIR (=/usr/local/kde on my system)
$QTDIR   (=/usr/local/qt on my system)
before falling over with an error message.

Angus