failing to build a QJson app for Windows, from Debian

Question

My source code:

#include <qjson/serializer.h>
#include <QDebug>

int main() {
   QVariantMap numbers;
   numbers.insert("one", 1);
   numbers.insert("two", 2);

   QJson::Serializer serializer;
   qDebug() << serializer.serialize(numbers);

   return 0;
}

My project file:

TEMPLATE = app
LIBS += -lqjson
SOURCES += main.cpp

This works well if I build (and run) it on Debian:

$ qmake && make 
g++ -c -m64 -pipe -O2 -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++-64 -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -o main.o main.cpp
g++ -m64 -Wl,-O1 -o jsongen main.o    -L/usr/lib/x86_64-linux-gnu -lqjson -lQtGui -lQtCore -lpthread 
$ ./jsongen
"{ "one" : 1, "two" : 2 }" 

It however fails if I build it for Windows:

$ i686-pc-mingw32-qmake && make 
make -f Makefile.Release
make[1]: Entering directory `/home/wena/src/dcp/apps/j1939/winapp/play'
i686-pc-mingw32-g++ -c -pipe -fno-keep-inline-dllexport -O2 -frtti -fexceptions -mthreads -Wall -Wextra -DUNICODE -DQT_LARGEFILE_SUPPORT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_THREAD_SUPPORT -I'/home/wena/src/mxe/usr/i686-pc-mingw32/qt/include/QtCore' -I'/home/wena/src/mxe/usr/i686-pc-mingw32/qt/include/QtGui' -I'/home/wena/src/mxe/usr/i686-pc-mingw32/qt/include' -I'/home/wena/src/mxe/usr/i686-pc-mingw32/qt/include/ActiveQt' -I'release' -I'/home/wena/src/mxe/usr/i686-pc-mingw32/qt/mkspecs/win32-g++-4.6' -o release/main.o main.cpp
i686-pc-mingw32-g++ -Wl,-s -mthreads -Wl,-subsystem,windows -o release/jsongen.exe release/main.o  -L'/home/wena/src/mxe/usr/i686-pc-mingw32/qt/lib' -L'/home/wena/src/mxe/usr/i686-pc-mingw32/qt/lib' -lmingw32 -lqtmain -lqjson -lQtGui -lgdi32 -lcomdlg32 -loleaut32 -limm32 -lwinmm -lwinspool -lmsimg32 -lmng -llcms -L/home/wena/src/mxe/usr/i686-pc-mingw32/lib -ltiff -llzma -ljpeg -lQtCore -lpng -lole32 -luuid -lws2_32 -ladvapi32 -lshell32 -luser32 -lkernel32 -lz 
release/main.o:main.cpp:(.text.startup+0xcc): undefined reference to `_imp___ZN5QJson10SerializerC1Ev'
release/main.o:main.cpp:(.text.startup+0xf2): undefined reference to `_imp___ZN5QJson10Serializer9serializeERK8QVariant'
/home/wena/src/mxe/usr/lib/gcc/i686-pc-mingw32/4.7.2/../../../../i686-pc-mingw32/bin/ld: release/main.o: bad reloc address 0xf2 in section `.text.startup'
/home/wena/src/mxe/usr/lib/gcc/i686-pc-mingw32/4.7.2/../../../../i686-pc-mingw32/bin/ld: final link failed: Invalid operation
collect2: error: ld returned 1 exit status
make[1]: *** [release/jsongen.exe] Error 1
make[1]: Leaving directory `/home/wena/src/dcp/apps/j1939/winapp/play'
make: *** [release] Error 2

Note that the cross-build environment, e.g. Qt (4.8.3), QJson (0.7.1), and i686-pc-mingw32-qmake, was built with the help of MXE:

$ cd <path to mxe root>
$ make qjson
(wait about an hour on a recent machine with decent internet connection)
$ export PATH=<path to mxe root>:$PATH

Answer 1

I went for the simpler solution of putting qt-json, a simpler alternative, into my repository. The changes needed weren't much:

$ cat main.cpp 
#include "qt-json/json.h"
#include <QDebug>

int main() {
   QVariantMap numbers;
   numbers.insert("one", 1);
   numbers.insert("two", 2);

   QtJson::Json json;
   qDebug() << json.serialize(numbers);

   return 0;
}
$ cat jsongen.pro 
TEMPLATE = app
SOURCES += main.cpp
HEADERS += qt-json/json.h
SOURCES += qt-json/json.cpp