ref: 1eca33b48c25d3ee58691ea8f9d122cdf12a57a6
dir: /sys/src/ape/lib/ap/plan9/umask.c/
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
/*
* No such concept in plan9, but supposed to be always successful
*/
mode_t
umask(mode_t)
{
return 0;
}