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, 1 deletions

diff --git a/networking/telnetd.c b/networking/telnetd.c
index 108bbf44f..0201d2636 100644
--- a/networking/telnetd.c
+++ b/networking/telnetd.c
@@ -394,7 +394,7 @@ static void handle_sigchld(int sig)
 
         /* Looping: more than one child may have exited */
         while (1) {
-                pid = waitpid(-1, NULL, WNOHANG);
+                pid = wait_any_nohang(NULL);
                 if (pid <= 0)
                         break;
                 ts = sessions;