QT Compile on Linux: Cross Compilation failed with mxe / mingw / Linux, Debian

Question

I cannot compile the Windows Wallet, it shows me everytime this Error: What have I missed here? I am Using Debian.

Source Code: https://github.com/rat4/blackcoin

Content of compile-gtc.sh:

#!/bin/bash
MXE_INCLUDE_PATH=/mnt/mxe/usr/i686-w64-mingw32.static/include
MXE_LIB_PATH=/mnt/mxe/usr/i686-w64-mingw32.static/lib

i686-w64-mingw32.static-qmake-qt5 \
    BOOST_LIB_SUFFIX=-mt \
    BOOST_THREAD_LIB_SUFFIX=_win32-mt \
    BOOST_INCLUDE_PATH=$MXE_INCLUDE_PATH/boost \
    BOOST_LIB_PATH=$MXE_LIB_PATH \
    OPENSSL_INCLUDE_PATH=$MXE_INCLUDE_PATH/openssl \
    OPENSSL_LIB_PATH=$MXE_LIB_PATH \
    BDB_INCLUDE_PATH=$MXE_INCLUDE_PATH \
    BDB_LIB_PATH=$MXE_LIB_PATH \
    MINIUPNPC_INCLUDE_PATH=$MXE_INCLUDE_PATH \
    MINIUPNPC_LIB_PATH=$MXE_LIB_PATH \
    QMAKE_LRELEASE=/mnt/mxe/usr/i686-w64-mingw32.static/qt5/bin/lrelease blackcoin-qt.pro

make -f Makefile.Release

After some minutes i started ./compile-gtc.sh I got this Error:

/mnt/mxe/usr/i686-w64-mingw32.static/lib/libdb_cxx.a(os_pid.o):os_pid.c:(.text+0x25): undefined reference to `pthread_self' collect2: error: ld returned 1 exit status Makefile.Release:427: recipe for target 'release/blackcoin-qt.exe' failed make: *** [release/blackcoin-qt.exe] Error 1

Thank you,