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, 3 insertions, 6 deletions

diff --git a/miscutils/devfsd.c b/miscutils/devfsd.c
index 50c8203cb..1b88f050e 100644
--- a/miscutils/devfsd.c
+++ b/miscutils/devfsd.c
@@ -390,8 +390,8 @@ int devfsd_main(int argc, char **argv)
         sigemptyset(&new_action.sa_mask);
         new_action.sa_flags = 0;
         new_action.sa_handler = signal_handler;
-        sigaction(SIGHUP, &new_action, NULL);
-        sigaction(SIGUSR1, &new_action, NULL);
+        sigaction_set(SIGHUP, &new_action);
+        sigaction_set(SIGUSR1, &new_action);
 
         printf("%s v%s started for %s\n", applet_name, DEVFSD_VERSION, mount_point);
 
diff --git a/miscutils/rx.c b/miscutils/rx.c
index 9a8fcaa20..48867b83c 100644
--- a/miscutils/rx.c
+++ b/miscutils/rx.c
@@ -220,7 +220,6 @@ static void sigalrm_handler(int ATTRIBUTE_UNUSED signum)
 int rx_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int rx_main(int argc, char **argv)
 {
-        struct sigaction act;
         struct termios tty, orig_tty;
         int termios_err;
         int file_fd;
@@ -243,9 +242,7 @@ int rx_main(int argc, char **argv)
         }
 
         /* No SA_RESTART: we want ALRM to interrupt read() */
-        memset(&act, 0, sizeof(act));
-        act.sa_handler = sigalrm_handler;
-        sigaction(SIGALRM, &act, NULL);
+        signal_no_SA_RESTART_empty_mask(SIGALRM, sigalrm_handler);
 
         n = receive(file_fd);