Fix a race condition when building on Mac
Fix a race condition when building on Mac

Updating deploy.pri based on Qt's qbase.pri.

Without this logic both Makefile.Release and Makefile.Debug have the
same contents which creates a race condition to create the Headers
symlink in the framework.

This logic ensures there is only 1 set of commands that creates
the symlink.

enthought/qt-mobility,tmcguire/qt-mobility,enthought/qt-mobility,kaltsi/qt-mobility,enthought/qt-mobility,qtproject/qt-mobility,tmcguire/qt-mobility,kaltsi/qt-mobility,KDE/android-qt-mobility,kaltsi/qt-mobility,tmcguire/qt-mobility,tmcguire/qt-mobility,kaltsi/qt-mobility,qtproject/qt-mobility,kaltsi/qt-mobility,KDE/android-qt-mobility,qtproject/qt-mobility,enthought/qt-mobility,qtproject/qt-mobility,enthought/qt-mobility,KDE/android-qt-mobility,enthought/qt-mobility,qtproject/qt-mobility,qtproject/qt-mobility,KDE/android-qt-mobility,tmcguire/qt-mobility,kaltsi/qt-mobility