By default RTEMS does not support linux extensions for errno.
Enable it for build.
Change-Id: I43b346794b99ac0ed339bfbe6e39684071615503
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Ryan Chu <ryan.chu@qt.io>