chg: make timeout adjustable

Before this patch, chg will give up when it cannot connect to the new server
within 10 seconds. If the host has high load during that time, 10 seconds
is not enough.

This patch makes it adjustable using the CHGTIMEOUT environment variable.

contrib/chg/README

@@ -28,3 +28,5 b' The following variables are available fo'
 
  * CHGDEBUG enables debug messages.
  * CHGSOCKNAME specifies the socket path of the background cmdserver.
+ * CHGTIMEOUT specifies how many seconds chg will wait before giving up
+   connecting to a cmdserver. If it is 0, chg will wait forever. Default: 10

contrib/chg/chg.c

@@ -249,7 +249,13 b' static hgclient_t *retryconnectcmdserver'
 	int pst = 0;
 
 	debugmsg("try connect to %s repeatedly", opts->sockname);
-	for (unsigned int i = 0; i < 10 * 100; i++) {
+
+	unsigned int timeoutsec = 10;  /* default: 10 seconds */
+	const char *timeoutenv = getenv("CHGTIMEOUT");
+	if (timeoutenv)
+		sscanf(timeoutenv, "%u", &timeoutsec);
+
+	for (unsigned int i = 0; !timeoutsec || i < timeoutsec * 100; i++) {
 		hgclient_t *hgc = hgc_open(opts->sockname);
 		if (hgc)
 			return hgc;