There's a lot of code now requiring it. Any compiler that doesn't
support the keyword is too old for Qt now. The last time anyone asked
about this macro was for QTBUG-27393 and we don't know which compiler
that was.
As a necessity, this patch contains a reversal of
a0c3a57aed
[ChangeLog][Compiler Specific Changes] Qt 5.5 now unconditionally uses
the "using" keyword. Compilers that do not support this keyword are
deprecated and will not be able to build Qt. Previous versions of Qt may
or may not compile, as no testing was done to ensure it worked.
Change-Id: Ief042f34aba555a095d1f342a0ee7ee9feadf42d
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>
2e4b1a8334