title: C++ Qt MingW bad reloc 0xc address in section rdata
body: <p>I'm with Qt 5.5 on Windows 10 64 bit with MingW compiler.<br>
  I'm trying to compile my project in debug mode => Works perfectly<br>
  But in release mode, I have these errors:</p>
  
  <pre><code>undefined reference to `TileMap::XYToNode(int, int) const'
  undefined reference to `TileMap::XYToNode(int, int) const'  
  ./release\perso.o: bad reloc address 0xc in section `.rdata'  
  collect2.exe:-1: erreur : error: ld returned 1 exit status  
  </code></pre>
  
  <p>I have tried to do clean, qmake, and rebuild, but there are still errors.<br>
  I use some SFML dlls, and dlls I created. My TileMap class inherits a SFML class, and a micropather class (which is in one of the dlls).</p>
  
  <p><em>Yes, I have tried Google before.</em></p>
  
  <p>The .pro file:  </p>
  
  <pre><code>    TEMPLATE = app  
      TARGET = TealDemo  
      QT = widgets  
  
  SOURCES += ........  
  
  LIBS += -LC:/Qt/5.5/SFML/lib -LC:/Qt/5.5/micropather/lib -LC:/Qt/5.5/pathstore/lib
  
  CONFIG(release): LIBS += -lsfml-graphics -lsfml-main -lsfml-window -lsfml-system -lmp -lpathstore  
  CONFIG(debug): LIBS += -lsfml-graphics-d -lsfml-main-d -lsfml-window-d -lsfml-system-d -lmpd -lpathstored  
  
  INCLUDEPATH += C:/Qt/5.5/SFML/include C:/Qt/5.5/micropather/include C:/Qt/5.5/pathstore/include  
  DEPENDPATH += C:/Qt/5.5/SFML/include C:/Qt/5.5/micropather/include C:/Qt/5.5/pathstore/include  
  
  HEADERS += .......
  
  CONFIG += C++11 warn_on  
  
  debug {  
      DEFINES += TEAL_DEBUG  
  } 
  </code></pre>
  
  <p>How to resolve this ?<br>
  Thanks</p>