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, 6 insertions, 4 deletions

diff --git a/runit/runsv.c b/runit/runsv.c
index e1d99e2df..02271d68b 100644
--- a/runit/runsv.c
+++ b/runit/runsv.c
@@ -345,8 +345,10 @@ static void startservice(struct svdir *s)
                                 xdup2(logpipe.wr, 1);
                         }
                 }
-                signal(SIGCHLD, SIG_DFL);
-                signal(SIGTERM, SIG_DFL);
+                bb_signals(0
+                        + (1 << SIGCHLD)
+                        + (1 << SIGTERM)
+                        , SIG_DFL);
                 sig_unblock(SIGCHLD);
                 sig_unblock(SIGTERM);
                 execvp(*run, run);
@@ -460,9 +462,9 @@ int runsv_main(int argc, char **argv)
         ndelay_on(selfpipe.wr);
 
         sig_block(SIGCHLD);
-        sig_catch(SIGCHLD, s_child);
+        bb_signals_recursive(1 << SIGCHLD, s_child);
         sig_block(SIGTERM);
-        sig_catch(SIGTERM, s_term);
+        bb_signals_recursive(1 << SIGTERM, s_term);
 
         xchdir(dir);
         /* bss: svd[0].pid = 0; */