Add recursion depth protection to LIKE matching.

Since MatchText() recurses, it could in principle be driven to stack
overflow, although quite a long pattern would be needed.

src/backend/utils/adt/like.c

@@ -21,6 +21,7 @@
 
 #include "catalog/pg_collation.h"
 #include "mb/pg_wchar.h"
+#include "miscadmin.h"
 #include "utils/builtins.h"
 #include "utils/pg_locale.h"
 

src/backend/utils/adt/like_match.c

@@ -83,6 +83,9 @@ MatchText(char *t, int tlen, char *p, int plen,
 	if (plen == 1 && *p == '%')
 		return LIKE_TRUE;
 
+	/* Since this function recurses, it could be driven to stack overflow */
+	check_stack_depth();
+
 	/*
 	 * In this loop, we advance by char when matching wildcards (and thus on
 	 * recursive entry to this function we are properly char-synced). On other