Synopsys   : FILTER_CAN_SEE(x, l)

Defined in : /sys/filter_funs.h

Description: This filter returns all objects in array 'x' that can be seen
             by living 'l'. The macro CAN_SEE is used to determine this.
Arguments  : object *x - the array with objects to filter.
Returns    : object *  - an array with only objects in it that 'l' can see.
