title: Qbs does not add Qt libraries when linking application
body: <p>I installed VS2015 and QtCreator 3.5 and compiled Qt5.5 from source as a binary distribution is not available for the visual c++ compiler shipped with VS2015.</p>
  
  <p>I tried to compile my project which was developed using the visual c++ compilers from VS2012/VS2013 and QtCreator 3.3x with Qt 5.2 and Qbs - on a different machine - from QtCreator and with my new setup neither QtCreator nor Qbs from command line are able to link the application.</p>
  
  <p>I narrowed the problem down using the Qbs helloworld example</p>
  
  <pre><code>import qbs
  
  CppApplication {
     type: "application" // To suppress bundle generation on Mac
     consoleApplication: true
     files: "main.cpp"
  
      Depends {
          name: "Qt"
          submodules: [
              "core"
          ]
      }
  }
  </code></pre>
  
  <p>Which gives the following output when building with qbs from the command line </p>
  
  <pre><code>compiling main.cpp
  linking halloqbswelt.exe
  ERROR: C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\BIN\amd64\link.exe /nologo /DEBUG /PDB:halloqbswelt.pdb /OSVERSION:5.02 /SUBSYSTEM:CONSOLE,5.02 /MANIFEST /MANIFESTFILE:D:\projekte\halloqbswelt\Qt5-debug\halloqbswelt.Qt5.842abbdf\intermediate.halloqbswelt.exe.manifest D:\projekte\halloqbswelt\Qt5-debug\halloqbswelt.Qt5.842abbdf\.obj\3a52ce780950d4d9\main.cpp.obj .lib /OUT:D:\projekte\halloqbswelt\Qt5-debug\halloqbswelt.Qt5.842abbdf\intermediate.halloqbswelt.exe /LIBPATH:D:\projekte\3rd_party\qt\qtbase\lib
  LINK : fatal error LNK1104: cannot open file '.lib'
  ERROR: Process failed with exit code 1104.
  The following products could not be built for configuration Qt5-debug:
      halloqbswelt
  </code></pre>
  
  <p>Rather cryptic so I'll highlight the problem from the above output</p>
  
  <pre><code>[...] .obj\3a52ce780950d4d9\main.cpp.obj .lib /OUT: [...]
  </code></pre>
  
  <p>So the empty .lib file is the problem. </p>
  
  <p>Comparing the linker statement with that from the other machine, the empty .lib is at the same position where Qt5Core.lib should be.
  Thus tried to investigate why Qbs does not resolve the paths proberly; I looked at the core.qbs module but couldn't find anything different from the file on the machine with the working setup.
  Finally I decided to recompile the Qt library and setup the Qbs/QtCreator profiles from scratch. Done and it worked, until I restarted QtCreator, now neither (Qbs from command line, nor QtCreator with its own profile) works anymore.</p>
  
  <p>Has somebody experienced such a behavior?</p>