The problem is building against the 10.12 or later SDK but deploying to 10.11
or earlier.  Support for clock_gettime() is new with 10.12 so configure finds
it and the code uses it, but the symbol is weak linked and resolves to NULL
when running on earlier versions.
Signed-off-by: Ken Thomases <ken@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>