Automatically LoadLibrary("d3dcompiler_43.dll") - RHBZ #1057983
    
    - Automatically LoadLibrary("d3dcompiler_43.dll") when no other D3D compiler is
      already loaded yet. Fixes RHBZ #1057983
    - Make sure the libraries are built with debugging symbols
    - Rebuild against latest mingw-w64 (fixes Windows XP compatibility, RHBZ #1054481)