ref: f5960a5c076adc9b608e51a537014e99de2adf54
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 numask)
{
return 0;
}