secflag_clear
secflag_clear(&val, PROC_SEC_ASLR);
secflag_clear(&val, PROC_SEC_FORBIDNULLMAP);
secflag_clear(&val, PROC_SEC_NOEXECSTACK);
secflag_clear(&flags, fd->value);
secflag_clear(&p->p_secflags.psf_effective, flag);
extern void secflag_clear(secflagset_t *, secflag_t);