Qt 5.2.1 using MinGW 4.4
Just reporting in case anyone is wondering if it is possible to compile Qt 5.2.1 with MinGW 4.4. It is.
I needed to use MinGW 4.4 because one of my libraries was not compatible with MinGW 4.8, nor 4.7.
Haven't tested on 4.6 or 4.5 but since Qt 4.8.5 was still using the 4.4 version I decided to try that since I used to use Qt 4.8 with this library.
The library is libxl, it seems that the last update makes it compatible with MinGW 4.7 but I have an older version and to get the newest I would have to buy a new license.
So I went and compiled Qt 5.2.1 with MinGW 4.4, I run into some problems but most of them I found a solution in forums while googling them. From what I have tested so far it is working great.
I ran into this problem after I switched from Qt 5.2.1 MSVC 2010 with ANGLE to Qt 5.2.1 MinGW 4.8 with OpenGL. I decided to change since I was using MSVC version just because of ANGLE, but it seems ANGLE isn't compatible with Windows XP and that became a problem for me.
I also found a Mesa llvmpipe DLL compiled for Windows and that means that if a computer doesn't have OpenGL ES 2, they can use that DLL to have OpenGL processed by the CPU instead of the GPU. Which means that I can deploy it everywhere again (as long as it is not graphics intensive) like I did before with Qt 4.8.
(In case you want to try the DLL: http://qt-project.org/wiki/Cross-compiling-Mesa-for-Windows)
If there is enough interest I guess I can try it again and this time document everything.
Good research, thanks for sharing.