wrlib: re-introduce the optimize_for_speed flag for binary compatibility
The commit #
d1f9b801 removed it because the code behind it is actually
useless, unfortunately removing the flag itself from the structure is
breaking the compatibility of the API.
To avoid problems, this patch re-introduces the flag in the structure, but
not the code behind it so it is useless, and adds an attribute so that gcc
will report its use as deprecated, to help application migration.
Signed-off-by: Christophe CURIS <christophe.curis@free.fr>