ref: e01d88046c40bb23331fb5bd45b9f27d61eb3fe5
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;
}