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

libbb/signals.c

@@ -0,0 +1,80 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
+ * Copyright (C) 2006 Rob Landley
+ * Copyright (C) 2006 Denis Vlasenko
+ *
+ * Licensed under GPL version 2, see file LICENSE in this tarball for details.
+ */
+
+#include "libbb.h"
+
+void bb_signals(int sigs, void (*f)(int))
+{
+	int sig_no = 0;
+	int bit = 1;
+
+	while (sigs) {
+		if (sigs & bit) {
+			sigs &= ~bit;
+			signal(sig_no, f);
+		}
+		sig_no++;
+		bit <<= 1;
+	}
+}
+
+void bb_signals_recursive(int sigs, void (*f)(int))
+{
+	int sig_no = 0;
+	int bit = 1;
+	struct sigaction sa;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = f;
+	/*sa.sa_flags = 0;*/
+	/*sigemptyset(&sa.sa_mask); - hope memset did it*/
+
+	while (sigs) {
+		if (sigs & bit) {
+			sigs &= ~bit;
+			sigaction(sig_no, &sa, NULL);
+		}
+		sig_no++;
+		bit <<= 1;
+	}
+}
+
+void sig_block(int sig)
+{
+	sigset_t ss;
+	sigemptyset(&ss);
+	sigaddset(&ss, sig);
+	sigprocmask(SIG_BLOCK, &ss, NULL);
+}
+
+void sig_unblock(int sig)
+{
+	sigset_t ss;
+	sigemptyset(&ss);
+	sigaddset(&ss, sig);
+	sigprocmask(SIG_UNBLOCK, &ss, NULL);
+}
+
+#if 0
+void sig_blocknone(void)
+{
+	sigset_t ss;
+	sigemptyset(&ss);
+	sigprocmask(SIG_SETMASK, &ss, NULL);
+}
+#endif
+
+void sig_pause(void)
+{
+	sigset_t ss;
+	sigemptyset(&ss);
+	sigsuspend(&ss);
+}