sigchld_mask      521 src/subshell/common.c     sigset_t sigchld_mask, old_mask;
sigchld_mask      523 src/subshell/common.c     sigemptyset (&sigchld_mask);
sigchld_mask      524 src/subshell/common.c     sigaddset (&sigchld_mask, SIGCHLD);
sigchld_mask      525 src/subshell/common.c     sigprocmask (SIG_BLOCK, &sigchld_mask, &old_mask);