Issue #10141: fix socketmodule compilation on Linux systems with <linux/can.h> but without AF_CAN definition.
Issue #10141: fix socketmodule compilation on Linux systems with <linux/can.h>
but without AF_CAN definition.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator