libbb: introduce and use safe_waitpid (loops in EINTR)

*: use more approproate (shorter) versions of wait()

function                                             old     new   delta
safe_waitpid                                           -      48     +48
wait_any_nohang                                        -      17     +17
send_tree                                            365     369      +4
processorstop                                        432     435      +3
text_yank                                            110     108      -2
make_human_readable_str                              202     200      -2
crond_main                                          1368    1366      -2
handle_sigchld                                        49      43      -6
reapchild                                            166     159      -7
custom                                               260     250     -10
checkscript                                          191     177     -14
wait_nohang                                           17       -     -17
wait_pid                                              43       -     -43
------------------------------------------------------------------------------
(add/remove: 2/2 grow/shrink: 2/7 up/down: 72/-103)           Total: -31 bytes

1 files changed, 1 insertions, 0 deletions

diff --git a/shell/hush.c b/shell/hush.c
index cb2c3e98e..b08fe10b6 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -1649,6 +1649,7 @@ static int checkjobs(struct pipe* fg_pipe)
 // + killall -STOP cat
 
  wait_more:
+// TODO: safe_waitpid?
         while ((childpid = waitpid(-1, &status, attributes)) > 0) {
                 const int dead = WIFEXITED(status) || WIFSIGNALED(status);