When a class inherits from `Loggable`, it will have a protected `_log()`
function and that will be used instead of the global `_log()` function in the
expansion of the `LOG()` macro. However, if such a class has static member
functions, then simply writing `LOG()` will not work because name lookup will
find the non-static member function and not the global function, resulting in
a compiler error because the non-static member cannot be invoked without an
object, and there is no object in a static member function.
This can be avoided by using `using libcamera::_log;`, thereby bringing the
global declaration into the current scope.
Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
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