For GUC values, check for partial string matches on 'on' and 'off', but

require at least two characters for uniqueness.   This now matches the
behavior of other boolean strings we support, per report from Gurjeet
Singh.

src/backend/utils/misc/guc.c

@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.362 2006/12/13 05:54:48 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.363 2006/12/23 00:52:40 momjian Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -3575,12 +3575,13 @@ parse_bool(const char *value, bool *result)
 			*result = false;
 	}
 
-	else if (pg_strcasecmp(value, "on") == 0)
+	/* 'o' is not unique enough */
+	else if (pg_strncasecmp(value, "on", (len > 2 ? len : 2)) == 0)
 	{
 		if (result)
 			*result = true;
 	}
-	else if (pg_strcasecmp(value, "off") == 0)
+	else if (pg_strncasecmp(value, "off", (len > 2 ? len : 2)) == 0)
 	{
 		if (result)
 			*result = false;