Build fails in tools/assistant/ with "libQtHelp.so, not found"

Trying to build Qt's 4.6 branch from git, I see this error:

make[4]: Entering directory `/home/murrayc/checkouts/gnome/qt/tools/assistant/tools/assistant'
g++ -L/opt/gnome228/lib -Wl,-O1 -Wl,-rpath,/opt/gnome228/lib -Wl,-rpath,/opt/gnome228/lib -o ../../../../bin/assistant .obj/release-shared/fontpanel.o .obj/release-shared/helpviewer.o .obj/release-shared/main.o .obj/release-shared/mainwindow.o .obj/release-shared/indexwindow.o .obj/release-shared/topicchooser.o .obj/release-shared/contentwindow.o .obj/release-shared/searchwidget.o .obj/release-shared/preferencesdialog.o .obj/release-shared/filternamedialog.o .obj/release-shared/centralwidget.o .obj/release-shared/installdialog.o .obj/release-shared/bookmarkmanager.o .obj/release-shared/remotecontrol.o .obj/release-shared/cmdlineparser.o .obj/release-shared/aboutdialog.o .obj/release-shared/qtdocinstaller.o .obj/release-shared/moc_fontpanel.o .obj/release-shared/moc_helpviewer.o .obj/release-shared/moc_mainwindow.o .obj/release-shared/moc_indexwindow.o .obj/release-shared/moc_topicchooser.o .obj/release-shared/moc_contentwindow.o .obj/release-shared/moc_searchwidget.o .obj/release-shared/moc_preferencesdialog.o .obj/release-shared/moc_filternamedialog.o .obj/release-shared/moc_centralwidget.o .obj/release-shared/moc_installdialog.o .obj/release-shared/moc_bookmarkmanager.o .obj/release-shared/moc_remotecontrol.o .obj/release-shared/moc_aboutdialog.o .obj/release-shared/moc_qtdocinstaller.o .obj/release-shared/qrc_assistant.o .obj/release-shared/qrc_assistant_images.o -L/home/murrayc/checkouts/gnome/qt/lib -L/home/murrayc/checkouts/gnome/qt/plugins/sqldrivers -lQtHelp -L/home/murrayc/checkouts/gnome/qt/lib -L/usr/X11R6/lib -lQtWebKit -lphonon -lQtDBus -lQtXmlPatterns -lQtSql -lQtXml -lQtGui -lQtNetwork -lQtCore -lpthread
/usr/bin/ld: warning: libQtCLucene.so.4, needed by /home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so, not found (try using -rpath or -rpath-link)
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexWriter::setMergeFactor(int)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexReader::isLocked(QString const&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexSearcher::close()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneDocument::get(QString const&) const'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexSearcher::QCLuceneIndexSearcher(QString const&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneBooleanQuery::QCLuceneBooleanQuery()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneHits::length() const'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexWriter::QCLuceneIndexWriter(QString const&, QCLuceneAnalyzer&, bool, bool)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneStopAnalyzer::QCLuceneStopAnalyzer()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneBooleanQuery::~QCLuceneBooleanQuery()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneHits::~QCLuceneHits()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexReader::~QCLuceneIndexReader()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexReader::close()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexReader::unlock(QString const&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneQueryParser::parse(QString const&, QString const&, QCLuceneAnalyzer&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexSearcher::~QCLuceneIndexSearcher()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneTermQuery::QCLuceneTermQuery(QCLuceneTerm const&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexReader::deleteDocuments(QCLuceneTerm const&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexWriter::close()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLucenePhraseQuery::addTerm(QCLuceneTerm const&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneTermQuery::~QCLuceneTermQuery()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneStopAnalyzer::~QCLuceneStopAnalyzer()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneBooleanQuery::add(QCLuceneQuery*, bool, bool, bool)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneStandardAnalyzer::QCLuceneStandardAnalyzer()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexWriter::setMinMergeDocs(int)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneStopAnalyzer::englishStopWords() const'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneDocument::clear()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneTerm::QCLuceneTerm(QString const&, QString const&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexWriter::setMaxFieldLength(int)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLucenePhraseQuery::QCLucenePhraseQuery()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneStandardAnalyzer::~QCLuceneStandardAnalyzer()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexWriter::addDocument(QCLuceneDocument&, QCLuceneAnalyzer&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneSearcher::search(QCLuceneQuery const&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneDocument::QCLuceneDocument()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneQuery::toString() const'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneDocument::~QCLuceneDocument()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexReader::open(QString const&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneDocument::add(QCLuceneField*)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneHitsPrivate::~QCLuceneHitsPrivate()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexWriter::optimize()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneField::QCLuceneField(QString const&, QString const&, int)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexReader::indexExists(QString const&)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneTerm::~QCLuceneTerm()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneDocumentPrivate::~QCLuceneDocumentPrivate()'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneHits::document(int)'
/home/murrayc/checkouts/gnome/qt/lib/libQtHelp.so: undefined reference to `QCLuceneIndexWriter::~QCLuceneIndexWriter()'
collect2: ld returned 1 exit status
make[4]: *** [../../../../bin/assistant] Error 1
make[4]: Leaving directory `/home/murrayc/checkouts/gnome/qt/tools/assistant/tools/assistant'
make[3]: *** [sub-assistant-all-ordered] Error 2
make[3]: Leaving directory `/home/murrayc/checkouts/gnome/qt/tools/assistant/tools'
make[2]: *** [sub-tools-all-ordered] Error 2
make[2]: Leaving directory `/home/murrayc/checkouts/gnome/qt/tools/assistant'
make[1]: *** [sub-assistant-all-ordered] Error 2
make[1]: Leaving directory `/home/murrayc/checkouts/gnome/qt/tools'
make: *** [sub-tools-all-ordered] Error 2