libbb: introduse and use signal_[no_]SA_RESTART_empty_mask and sigaction_set

signal_SA_RESTART_empty_mask                           -      65     +65
signal_no_SA_RESTART_empty_mask                        -      54     +54
dd_main                                             1325    1369     +44
sigaction_set                                          -      19     +19
dname_enc                                            373     377      +4
UNSPEC_print                                          64      66      +2
setsignal                                            296     294      -2
bb_signals_recursive                                  95      92      -3
bb_askpass                                           367     361      -6
inetd_main                                          1810    1797     -13
rx_main                                              912     883     -29
sigdelset                                             32       -     -32
__sigdelset                                           32       -     -32
__GI_sigdelset                                        32       -     -32
sighup_handler                                        84      37     -47
arping_main                                         1844    1797     -47
fsck_main                                           1869    1807     -62
run_list                                            1917    1844     -73
vlock_main                                           492     409     -83
progressmeter                                        883     798     -85
handle_incoming_and_exit                            2737    2651     -86
------------------------------------------------------------------------------
(add/remove: 3/3 grow/shrink: 3/12 up/down: 188/-632)        Total: -444 bytes

2 files changed, 2 insertions, 12 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 9b1a73024..6f675ce69 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -3340,7 +3340,7 @@ setsignal(int signo)
         *t = action;
         act.sa_flags = 0;
         sigfillset(&act.sa_mask);
-        sigaction(signo, &act, NULL);
+        sigaction_set(signo, &act);
 }
 
 /* mode flags for set_curjob */
diff --git a/shell/hush.c b/shell/hush.c
index b44f35bdd..baa2db780 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -699,16 +699,6 @@ static const struct built_in_command bltins[] = {
 
 #if ENABLE_HUSH_JOB
 
-/* move to libbb? */
-static void signal_SA_RESTART(int sig, void (*handler)(int))
-{
-        struct sigaction sa;
-        sa.sa_handler = handler;
-        sa.sa_flags = SA_RESTART;
-        sigemptyset(&sa.sa_mask);
-        sigaction(sig, &sa, NULL);
-}
-
 /* Signals are grouped, we handle them in batches */
 static void set_fatal_sighandler(void (*handler)(int))
 {
@@ -2115,7 +2105,7 @@ static int run_list(struct pipe *pi)
 #if ENABLE_FEATURE_SH_STANDALONE
                 nofork_save.saved = 0; /* in case we will run a nofork later */
 #endif
-                signal_SA_RESTART(SIGTSTP, handler_ctrl_z);
+                signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z);
                 signal(SIGINT, handler_ctrl_c);
         }
 #endif /* JOB */