update of old PL/SQL PLpgSQL and SQLPL patch based on current version

see [linguist] add support for oracle PLSQL (#1003)

samples/SQLPL/trigger.sql

@@ -0,0 +1,9 @@
+create trigger CHECK_HIREDATE
+no cascade before insert on EMPLOYEE
+referencing new as N
+for each row mode db2sql
+if n.hiredate > current date
+then
+  signal SQLSTATE '75000'
+  set MESSAGE_TEXT = 'Hire date must be in the past';
+end if!