Locator bar does not find main function, depending on kit

1. Start Creator.
   Doing this with an already running Creator can lead to different results.
2. Create a new Qt Widgets Application.
3. Configure the project with a kit using Qt 4.8.0 built with MinGW.
4. Type "m main" into the Locator bar.
   Creator will only list MainWindow's ctor and dtor.
5. Configure the project with a kit using Qt 5.2.1 built with MinGW.
6. Type "m main" into the Locator bar.
   Creator will additionally list one signal, but not any main function.
7. Configure the project with a kit using Qt 5.2.1 built with MSVC 2010.
8. Type "m main" into the Locator bar.
   Creator will list two signals and five functions, including the main function.
9. Configure the project with a kit using Qt 4.8.0 built with MinGW.
10. Type "m main" into the Locator bar.
    Creator will list two signals and four functions, the main function is missing again.

It does not matter whether the clang code model or the built-in one are being used.

The Locator bar should always list the same functions, regardless of the selected kit. Now the displayed functions don't just depend on the active kit but even on the previously selected kits.
(#ifdef and functions used in one kit only are an exception of course.)