qt plugins and release builds

[Shane King]

Christian Ehrlicher wrote:
>>     if (WIN32)
>> 	  # qt is always compiled with QT_NO_DEBUG under mingw,
>> 	  # so we need to compile stuff linked against it
>> 	  # the same or otherwise QPluginLoader rejects plugins
>>        add_definitions(-DQT_NO_DEBUG)
>>     endif (WIN32)
>>
>> Hopefully this should solve our issues.
>>
> Please find another way to fix this!

Why? I explain why I think it's the correct fix (QT isn't compiled as 
seperate debug and release builds under mingw, just like on unix). It 
fixes it only for that compiler, in all circumstances. MSVC (or any 
other compiler) isn't affected.

The only other way I can see to fix this is to modify the way we compile 
QT and pass through -DQT_NO_DEBUG_PLUGIN_CHECK when compiling with 
mingw, since the check is superfluous for mingw as there really aren't 
"debug" and "release" versions of the library.

Shane.