I built two libraries Qt 5.3.1 using cross-compilers of the project MXE (http://mxe.cc)

Command line (gcc build with POSIX threads):

make MXE_TARGETS='x86_64-w64-mingw32.shared i686-w64-mingw32.shared' qt5

Then build a example "fancybrowser". Win32 version runs fine, but the Win64 version ends with by crash.
Runs under Windows 8.1 x64.
Version "fancybrowser" Qt 5.3.2 (Linux 64) also run fine.

Call Stack:

: Call Site
: Qt5Network!ZN9QHostInfo15localDomainNameEv+0x15a0
: Qt5Network!ZN20QNetworkProxyFactory19systemProxyForQueryERK18QNetworkProxyQuery+0x4b
: Qt5Network!Zls6QDebugRK13QNetworkProxy+0xd9e
: Qt5Network!ZN20QNetworkProxyFactory13proxyForQueryERK18QNetworkProxyQuery+0x41
: Qt5Network!ZN21QNetworkAccessManagerC2EP7QObject+0xf10
: Qt5Network!ZN13QNetworkReply5closeEv+0x10c2c
: Qt5Network!ZN13QNetworkReply5closeEv+0x12b22
: Qt5Network!ZN13QNetworkReply5closeEv+0x13048
: Qt5Network!ZN13QNetworkReply11qt_metacallEN11QMetaObject4CallEiPPv+0x8da
: Qt5Core!ZN7QObject5eventEP6QEvent+0xea
: Qt5Widgets!ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent+0x8c
: Qt5Widgets!ZN12QApplication6notifyEP7QObjectP6QEvent+0x42e
: Qt5Core!ZN16QCoreApplication14notifyInternalEP7QObjectP6QEvent+0x6c
: Qt5Core!ZN23QCoreApplicationPrivate16sendPostedEventsEP7QObjectiP11QThreadData+0x1d0
: qwindows+0x2c0d2
: Qt5Core!ZN28QEventDispatcherWin32Private14sendTimerEventEi+0x367
: user32!DispatchMessageW+0x154
: user32!IsThreadDesktopComposited+0x1f7
: Qt5Core!ZN21QEventDispatcherWin3213processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE+0x66a
: qwindows+0x2c171
: Qt5Core!ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE+0x1aa
: Qt5Core!ZN16QCoreApplication4execEv+0x77
: fancybrowser+0x1990
: fancybrowser+0x511f
: fancybrowser+0x13e8
: fancybrowser+0x14eb
: kernel32!BaseThreadInitThunk+0xd
: ntdll!RtlUserThreadStart+0x1d

Dump file (WinDbg64) is attached.
Sorry for my bad English, I used Google translator.