Doc: Update description of qmake LIBS variable

Rewrite the note about specifying libraries on Windows
to make it clearer and change the library name to match the
one in the snippet.

Task-number: QTBUG-30229

Change-Id: I55c5579f5ead2fadc5d75baa2172b03f20c9f689
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Fix unused private field warning in QMacMime.

Does not apply to Qt 5.

Change-Id: Ia1e5c5d8813a2285dd80189f7264d959ea8056c1
Reviewed-by: David Faure (KDE) <faure@kde.org>
Update for OS X Mavericks.

(Qt 4 equivalent of qtbase/bd97768ae54d643270e824f74d152892dbea1b9f)

Change-Id: I7ecebd2e185d61a0baeb5b47b802c2f760edeff3
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>