QSaveFile: follow symbolic links

[ChangeLog][QtCore][QSaveFile] Now follows symbolic links while writing to
a link instead of replacing the link with the contents.

Change-Id: I5afd519cb9f96ae68fa4c23c33a18de75671a301
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: David Faure <david.faure@kdab.com>
Fix QMAKE_EXTRA_COMPILERS' depend_command being ignored

A typo caused qmake to stop output dependency information
added by the depend_command clause.

Task-number: QTBUG-13334
Change-Id: I00fabc87438ce94e80341e6f88aa2e0eaab57e19
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>