Crash when properties change

#0  0xb7fe1424 in __kernel_vsyscall ()
#1  0xb77cd941 in *__GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#2  0xb77d0d72 in *__GI_abort () at abort.c:92
#3  0xb78072c5 in __libc_message (do_abort=2, fmt=0xb78dc4b0 "*** glibc detected *** %s: %s: 0x%s ***\n")
    at ../sysdeps/unix/sysv/linux/libc_fatal.c:189
#4  0xb78113b1 in malloc_printerr (action=<optimized out>, str=0x6 <Address 0x6 out of bounds>, ptr=0x14786e50) at malloc.c:6283
#5  0xb78117ee in malloc_consolidate (av=<optimized out>) at malloc.c:5161
#6  0xb7813925 in _int_malloc (av=<optimized out>, bytes=<optimized out>) at malloc.c:4373
#7  0xb7815d9c in *__GI___libc_malloc (bytes=1322) at malloc.c:3660
#8  0xb7aaf95b in qMalloc(unsigned int) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#9  0xb7ab8edd in QByteArray::QByteArray(char const*) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#10 0xb7ba2e13 in QProcessEnvironment::systemEnvironment() () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#11 0x081223e2 in qbs::Internal::Executor::doBuild (this=0x1b034210, productsToBuild=...)
    at ../../../src/lib/buildgraph/executor.cpp:168
#12 0x08121ca9 in qbs::Internal::Executor::build (this=0x1b034210, productsToBuild=...)
    at ../../../src/lib/buildgraph/executor.cpp:125
#13 0x0811fe42 in qbs::Internal::InternalBuildJob::start (this=0x1484e160) at ../../../src/lib/api/internaljobs.cpp:234
#14 0x0811d902 in qbs::Internal::InternalBuildJob::qt_static_metacall (_o=0x1484e160, _c=QMetaObject::InvokeMetaMethod, _id=0, 
    _a=0x1bb6cad0) at moc_internaljobs.cpp:293
#15 0xb7bda78a in QMetaCallEvent::placeMetaCall(QObject*) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#16 0xb7bdeccb in QObject::event(QEvent*) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#17 0xb7bc8768 in QCoreApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#18 0xb7bc87d4 in QCoreApplication::notify(QObject*, QEvent*) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#19 0xb7bc855e in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#20 0xb7bcc76d in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) ()
   from /usr/lib/i386-linux-gnu/libQtCore.so.4
#21 0xb7bcc9ec in QCoreApplication::sendPostedEvents(QObject*, int) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#22 0xb7bfa6c4 in ?? () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#23 0xb76c86d3 in g_main_context_dispatch () from /lib/i386-linux-gnu/libglib-2.0.so.0
#24 0xb76c8a70 in ?? () from /lib/i386-linux-gnu/libglib-2.0.so.0
#25 0xb76c8b51 in g_main_context_iteration () from /lib/i386-linux-gnu/libglib-2.0.so.0
#26 0xb7bfa841 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
   from /usr/lib/i386-linux-gnu/libQtCore.so.4
#27 0xb7bc702c in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#28 0xb7bc7321 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#29 0xb7bcca9a in QCoreApplication::exec() () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#30 0x08054132 in main (argc=1, argv=0xbffff3b4) at ../../../../src/app/qbs/main.cpp:83