MINOR: init: report in "haproxy -c" whether there were warnings or not

This helps quickly checking if the config produces any warning. For
this we reuse the "warned" bit field to add a new WARN_ANY bit that is
set by ha_warning(). The rest of the bit field was also cleaned from
unused bits.

doc/management.txt

@@ -193,7 +193,7 @@ list of options is :
 
   -c : only performs a check of the configuration files and exits before trying
     to bind. The exit status is zero if everything is OK, or non-zero if an
-    error is encountered.
+    error is encountered. Presence of warnings will be reported if any.
 
   -d : enable debug mode. This disables daemon mode, forces the process to stay
     in foreground and to show incoming and outgoing events. It is equivalent to

include/types/global.h

@@ -242,13 +242,8 @@ extern int atexit_flag;
 extern unsigned char boot_seed[20];  // per-boot random seed (160 bits initially)
 
 /* bit values to go with "warned" above */
-/* unassigned : 0x00000001 (previously: WARN_BLOCK_DEPRECATED) */
-/* unassigned : 0x00000002 */
-/* unassigned : 0x00000004 (previously: WARN_REDISPATCH_DEPRECATED) */
-/* unassigned : 0x00000008 (previously: WARN_CLITO_DEPRECATED) */
-/* unassigned : 0x00000010 (previously: WARN_SRVTO_DEPRECATED) */
-/* unassigned : 0x00000020 (previously: WARN_CONTO_DEPRECATED) */
-#define WARN_FORCECLOSE_DEPRECATED  0x00000040
+#define WARN_ANY                    0x00000001 /* any warning was emitted */
+#define WARN_FORCECLOSE_DEPRECATED  0x00000002
 
 
 /* to be used with warned and WARN_* */

src/haproxy.c

@@ -2101,6 +2101,9 @@ static void init(int argc, char **argv)
 		struct peers *pr;
 		struct proxy *px;
 
+		if (warned & WARN_ANY)
+			qfprintf(stdout, "Warnings were found.\n");
+
 		for (pr = cfg_peers; pr; pr = pr->next)
 			if (pr->peers_fe)
 				break;

src/log.c

@@ -1123,6 +1123,8 @@ void ha_warning(const char *fmt, ...)
 {
 	va_list argp;
 
+	warned |= WARN_ANY;
+
 	if (!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE)) {
 		va_start(argp, fmt);
 		print_message("WARNING", fmt, argp);