add -s option to set bip homedir

bip.1

@@ -23,6 +23,10 @@ Don't daemonize. Log into stderr.
 Use config_file as the configuration file. 
 If no config file is given, bip will try to open ~/.bip/bip.conf.
 
+.TP
+\fB-s\fP homedir
+Set bip home directory to homedir instead of $HOME/.bip.
+
 .TP
 \fB-h\fP
 Help.

src/bip.c

@@ -902,7 +902,7 @@ int main(int argc, char **argv)
 	conf_global_log_file = stderr;
 	conf_pid_file = NULL;
 
-	while ((ch = getopt(argc, argv, "hnf:")) != -1) {
+	while ((ch = getopt(argc, argv, "hnfs:")) != -1) {
 		switch (ch) {
 		case 'f':
 			confpath = strdup(optarg);
@@ -910,6 +910,9 @@ int main(int argc, char **argv)
 		case 'n':
 			conf_daemonize = 0;
 			break;
+		case 's':
+			conf_biphome = strdup(optarg);
+			break;
 		default:
 			usage(argv[0]);
 		}