Put back encoding-conversion step in processing of incoming queries;

I had inadvertently omitted it while rearranging things to support
length-counted incoming messages.  Also, change the parser's API back
to accepting a 'char *' query string instead of 'StringInfo', as the
latter wasn't buying us anything except overhead.  (I think when I put
it in I had some notion of making the parser API 8-bit-clean, but
seeing that flex depends on null-terminated input, that's not really
ever gonna happen.)

src/include/parser/gramparse.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: gramparse.h,v 1.25 2002/09/04 20:31:45 momjian Exp $
+ * $Id: gramparse.h,v 1.26 2003/04/27 20:09:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -15,7 +15,6 @@
 #ifndef GRAMPARSE_H
 #define GRAMPARSE_H
 
-#include "lib/stringinfo.h"
 #include "nodes/parsenodes.h"
 
 /* from parser.c */
@@ -24,7 +23,7 @@ extern Oid	param_type(int t);
 extern int	yylex(void);
 
 /* from scan.l */
-extern void scanner_init(StringInfo str);
+extern void scanner_init(const char *str);
 extern void scanner_finish(void);
 extern int	base_yylex(void);
 extern void yyerror(const char *message);