swrast: Build fix for darwin

Fixes regression from commit 64b1dc44495890cbc2c7c5509cb830264020998c

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90147
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
CC: Emil Velikov <emil.l.velikov@gmail.com>
CC: jon.turney@dronecode.org.uk
CC: ionic@macports.org
1 file changed