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, 2 insertions, 2 deletions

diff --git a/archival/tar.c b/archival/tar.c
index 5b19093e8..64975c428 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -610,7 +610,7 @@ static int writeTarFile(const int tar_fd, const int verboseFlag,
 
         if (gzipPid) {
                 int status;
-                if (waitpid(gzipPid, &status, 0) == -1)
+                if (safe_waitpid(gzipPid, &status, 0) == -1)
                         bb_perror_msg("waitpid");
                 else if (!WIFEXITED(status) || WEXITSTATUS(status))
                         /* gzip was killed or has exited with nonzero! */
@@ -688,7 +688,7 @@ static void handle_SIGCHLD(int status)
         /* Actually, 'status' is a signo. We reuse it for other needs */
 
         /* Wait for any child without blocking */
-        if (waitpid(-1, &status, WNOHANG) < 0)
+        if (wait_any_nohang(&status) < 0)
                 /* wait failed?! I'm confused... */
                 return;