QT_SHARED not defined

Qt's configure script has code to detect gnu make(if CFG_USE_GNUMAKE="auto"), but sets CFG_USE_GNUMAKE=no initially, so the check is never done.

Then, when generating the makefiles ("qmake/generators/unix"), it only includes PRL_EXPORT_DEFINES, which has QT_SHARED, if include_deps is true, and include_deps is only true if using gnumake.

The bug is that PRL_EXPORT_DEFINES should be included no matter what the value of include_deps is (as they are included in all cases with each of the other qmake generators), and qt should also be running the auto detection code for gnumake.