move qlocale_mac.mm to OBJECTIVE_SOURCES

This fixes a warning when loading qmake.pro in Qt Creator on OS X.

Change-Id: Iabd70f2b5b9615d0fb1563081f485e6a4c828823
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Liang Qi <liang.qi@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
QDateTime: Add more tests for parsing/writing timezone offsets

The tests for toString/fromString previously didn't run tests
for timezones with hh:mm where mm != 00.

Change-Id: I74da99c5b6890f46ce06446084a8129b4cbc7a02
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: John Layt <jlayt@kde.org>
QDateTime: Fix sign handling in the timezone offset parser

Previously, parsing negative timezone offsets with minutes != 00
produced wrong results.

Examples (in -> out)
-00:15 -> +00:15
-01:15 -> -00:45

Change-Id: I6fa30810a08bdf2996365661720b2e362e8aeb93
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: John Layt <jlayt@kde.org>
QDateTime: Fix sign handling in the timezone offset writer

Previously, this produced wrong results, for example -3:30
became -3:-30.

Change-Id: I10efdfb48e5542b917c86b29cf8a99bfc26f7fe0
Reviewed-by: John Layt <jlayt@kde.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>