JavaScriptCore: c++11 compile fix

Change-Id: I0de4140323db25765243748dfed8533bca39217c
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Merge remote-tracking branch 'origin/stable' into dev

Change-Id: I6498ca9158162e2c2b9db6867128ba4ae687f5f9