libbb: introduce bb_signals and bb_signals_recursive,

which sets same handler for many signals. sig_catch is nuked
(bb_signals_recursive is more descriptive name).
*: use them as appropriate. 

function                                             old     new   delta
bb_signals_recursive                                   -      95     +95
bb_signals                                             -      52     +52
run_command                                          258     273     +15
svlogd_main                                         1368    1377      +9
runsv_main                                          1746    1752      +6
runsvdir_main                                       1643    1646      +3
UNSPEC_print                                          64      66      +2
time_main                                           1128    1127      -1
...
resize_main                                          246     210     -36
sig_catch                                             63       -     -63
set_fatal_sighandler                                  85      14     -71
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 5/24 up/down: 182/-548)        Total: -366 bytes

1 files changed, 5 insertions, 3 deletions

diff --git a/networking/udhcp/signalpipe.c b/networking/udhcp/signalpipe.c
index 918abd02d..1486b3b2d 100644
--- a/networking/udhcp/signalpipe.c
+++ b/networking/udhcp/signalpipe.c
@@ -42,9 +42,11 @@ void udhcp_sp_setup(void)
         close_on_exec_on(signal_pipe.rd);
         close_on_exec_on(signal_pipe.wr);
         ndelay_on(signal_pipe.wr);
-        signal(SIGUSR1, signal_handler);
-        signal(SIGUSR2, signal_handler);
-        signal(SIGTERM, signal_handler);
+        bb_signals(0
+                + (1 << SIGUSR1)
+                + (1 << SIGUSR2)
+                + (1 << SIGTERM)
+                , signal_handler);
 }