Merging with mysql-5.1-bugfixing.

mysql-test/r/udf.result

@@ -38,8 +38,6 @@ ERROR HY000: Can't initialize function 'reverse_lookup'; Wrong number of argumen
 select reverse_lookup("127.0.0.1");
 select reverse_lookup(127,0,0,1);
 select reverse_lookup("localhost");
-reverse_lookup("localhost")
-NULL
 select avgcost();
 ERROR HY000: Can't initialize function 'avgcost'; wrong number of arguments: AVGCOST() requires two arguments
 select avgcost(100,23.76);

mysql-test/t/udf.test

@@ -51,14 +51,17 @@ select lookup("localhost");
 --error ER_CANT_INITIALIZE_UDF
 select reverse_lookup();
 
-# These two functions should return "localhost", but it's
+# These two function calls should return "localhost", but it's
 # depending on configuration, so just call them and don't log the result
 --disable_result_log
 select reverse_lookup("127.0.0.1");
 select reverse_lookup(127,0,0,1);
---enable_result_log
 
+# This function call may return different results depending on platform,
+# so ignore results (see Bug#52060).
 select reverse_lookup("localhost");
+--enable_result_log
+
 --error ER_CANT_INITIALIZE_UDF
 select avgcost();
 --error ER_CANT_INITIALIZE_UDF