$ gdb xxdiff
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This GDB was configured as "i686-pc-linux-gnu"...Using host libthread_db library "/lib/libthread_db.so.1".

(gdb) run --merge left ancestor right
Starting program: /home/derek/bin/xxdiff --merge left ancestor right
warning: Unable to find dynamic linker breakpoint function.
GDB will be unable to debug shared library initializers
and track explicitly loaded dynamic code.
[Thread debugging using libthread_db enabled]
[New Thread 16384 (LWP 11038)]
Detaching after fork from child process 11041.

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 16384 (LWP 11038)]
0x409a28a4 in mallopt () from /lib/libc.so.6
(gdb) bt
#0  0x409a28a4 in mallopt () from /lib/libc.so.6
#1  0x409a16bd in free () from /lib/libc.so.6
#2  0x4024535a in QPixmap::detach() () from /usr/qt/3/lib/libqt-mt.so.3
#3  0x4024ee52 in QPainter::begin(QPaintDevice const*, bool) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#4  0x402f29ab in QPainter::QPainter(QPaintDevice const*, bool) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#5  0x4061371f in QSGIStyle::drawPrimitive(QStyle::PrimitiveElement, QPainter*, QRect const&, QColorGroup const&, unsigned, QStyleOption const&) const ()
   from /usr/qt/3/lib/libqt-mt.so.3
#6  0x406161e3 in QSGIStyle::drawComplexControl(QStyle::ComplexControl, QPainter*, QWidget const*, QRect const&, QColorGroup const&, unsigned, unsigned, unsigned, QStyleOption const&) const () from /usr/qt/3/lib/libqt-mt.so.3
#7  0x40401d19 in QScrollBar::drawControls(unsigned, unsigned, QPainter*) const
    () from /usr/qt/3/lib/libqt-mt.so.3
#8  0x40401c15 in QScrollBar::drawControls(unsigned, unsigned) const ()
   from /usr/qt/3/lib/libqt-mt.so.3
#9  0x4040088d in QScrollBar::rangeChange() () from /usr/qt/3/lib/libqt-mt.so.3
#10 0x403ffd9b in QRangeControl::setRange(int, int) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#11 0x0807a4e0 in XxScrollView::adjustVerticalScrollbars(QSize const&) ()
#12 0x0807a2f1 in XxScrollView::adjustScrollbars() ()
#13 0x080b9754 in XxScrollView::qt_invoke(int, QUObject*) ()
---Type <return> to continue, or q <return> to quit---
#14 0x080b9b10 in XxCentralFrame::qt_invoke(int, QUObject*) ()
#15 0x402f0ca6 in QObject::activate_signal(QConnectionList*, QUObject*) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#16 0x402f0b54 in QObject::activate_signal(int) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#17 0x080b7fbe in XxApp::textSizeChanged() ()
#18 0x080b802a in XxApp::qt_invoke(int, QUObject*) ()
#19 0x402f0d2c in QObject::activate_signal(QConnectionList*, QUObject*) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#20 0x402f0b54 in QObject::activate_signal(int) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#21 0x080b892e in XxDiffs::nbLinesChanged() ()
#22 0x08092e18 in XxDiffs::splitSwapJoin(int, unsigned) ()
#23 0x0806e75d in XxApp::regionSplitSwapJoin() ()
#24 0x080b82a7 in XxApp::qt_invoke(int, QUObject*) ()
#25 0x402f0d2c in QObject::activate_signal(QConnectionList*, QUObject*) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#26 0x4062f42a in QSignal::signal(QVariant const&) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#27 0x4030aedd in QSignal::activate() () from /usr/qt/3/lib/libqt-mt.so.3
#28 0x403f3112 in QPopupMenu::accelActivated(int) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#29 0x40644d88 in QPopupMenu::qt_invoke(int, QUObject*) ()
---Type <return> to continue, or q <return> to quit---
   from /usr/qt/3/lib/libqt-mt.so.3
#30 0x402f0d2c in QObject::activate_signal(QConnectionList*, QUObject*) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#31 0x402f0e8d in QObject::activate_signal(int, int) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#32 0x406275f2 in QAccel::activated(int) () from /usr/qt/3/lib/libqt-mt.so.3
#33 0x4028e381 in QAccelPrivate::activate(QAccelItem*) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#34 0x4028cdcc in QAccelManager::dispatchAccelEvent(QWidget*, QKeyEvent*) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#35 0x4028bece in qt_dispatchAccelEvent(QWidget*, QKeyEvent*) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#36 0x40293c6c in QApplication::notify(QObject*, QEvent*) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#37 0x4028c448 in QAccelManager::tryAccelEvent(QWidget*, QKeyEvent*) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#38 0x4028be3e in qt_tryAccelEvent(QWidget*, QKeyEvent*) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#39 0x4022c971 in QETWidget::translateKeyEvent(_XEvent const*, bool) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#40 0x40227cf7 in QApplication::x11ProcessEvent(_XEvent*) ()
   from /usr/qt/3/lib/libqt-mt.so.3
#41 0x4023ed64 in QEventLoop::processEvents(unsigned) ()
---Type <return> to continue, or q <return> to quit---
   from /usr/qt/3/lib/libqt-mt.so.3
#42 0x402a6ab8 in QEventLoop::enterLoop() () from /usr/qt/3/lib/libqt-mt.so.3
#43 0x402a6968 in QEventLoop::exec() () from /usr/qt/3/lib/libqt-mt.so.3
#44 0x40294b41 in QApplication::exec() () from /usr/qt/3/lib/libqt-mt.so.3
#45 0x080745a3 in main ()
(gdb) 