Infrastructure for deducing Param types from context, in the same way

that the types of untyped string-literal constants are deduced (ie,
when coerce_type is applied to 'em, that's what the type must be).
Remove the ancient hack of storing the input Param-types array as a
global variable, and put the info into ParseState instead.  This touches
a lot of files because of adjustment of routine parameter lists, but
it's really not a large patch.  Note: PREPARE statement still insists on
exact specification of parameter types, but that could easily be relaxed
now, if we wanted to do so.

src/include/parser/parse_func.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: parse_func.h,v 1.44 2003/04/08 23:20:04 tgl Exp $
+ * $Id: parse_func.h,v 1.45 2003/04/29 22:13:11 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,6 +16,7 @@
 
 #include "parser/parse_node.h"
 
+
 /*
  *	This structure is used to explore the inheritance hierarchy above
  *	nodes in the type tree in order to disambiguate among polymorphic
@@ -49,7 +50,8 @@ extern FuncDetailCode func_get_detail(List *funcname, List *fargs,
 
 extern bool typeInheritsFrom(Oid subclassTypeId, Oid superclassTypeId);
 
-extern void make_fn_arguments(List *fargs,
+extern void make_fn_arguments(ParseState *pstate,
+							  List *fargs,
 							  Oid *actual_arg_types,
 							  Oid *declared_arg_types);