PL/pgSQL: rename gram.y to pl_gram.y

This makes the naming inside plpgsql consistent and distinguishes the
file from the backend's gram.y file.  It will also allow easier
refactoring of the bison make rules later on.

src/pl/plpgsql/src/Makefile

@@ -58,7 +58,7 @@ pl_gram.o pl_handler.o pl_comp.o pl_exec.o pl_funcs.o pl_scanner.o: plpgsql.h pl
 
 pl_gram.h: pl_gram.c ;
 
-pl_gram.c: gram.y
+pl_gram.c: pl_gram.y
 ifdef BISON
 	$(BISON) -d $(BISONFLAGS) -o $@ $<
 else

src/pl/plpgsql/src/gram.y → src/pl/plpgsql/src/pl_gram.y

 %{
 /*-------------------------------------------------------------------------
  *
- * gram.y				- Parser for the PL/pgSQL procedural language
+ * pl_gram.y			- Parser for the PL/pgSQL procedural language
  *
  * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *
  * IDENTIFICATION
- *	  src/pl/plpgsql/src/gram.y
+ *	  src/pl/plpgsql/src/pl_gram.y
  *
  *-------------------------------------------------------------------------
  */

src/pl/plpgsql/src/pl_scanner.c

@@ -40,7 +40,7 @@ IdentifierLookup plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_NORMAL;
  *
  * In certain contexts it is desirable to prefer recognizing an unreserved
  * keyword over recognizing a variable name.  Those cases are handled in
- * gram.y using tok_is_keyword().
+ * pl_gram.y using tok_is_keyword().
  *
  * For the most part, the reserved keywords are those that start a PL/pgSQL
  * statement (and so would conflict with an assignment to a variable of the
@@ -55,7 +55,7 @@ IdentifierLookup plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_NORMAL;
  *		 search is used to locate entries.
  *
  * Be careful not to put the same word in both lists.  Also be sure that
- * gram.y's unreserved_keyword production agrees with the second list.
+ * pl_gram.y's unreserved_keyword production agrees with the second list.
  */
 
 static const ScanKeyword reserved_keywords[] = {

src/tools/msvc/Mkvcbuild.pm

@@ -107,7 +107,7 @@ sub mkvcbuild
 
 	my $plpgsql =
 	  $solution->AddProject('plpgsql', 'dll', 'PLs', 'src\pl\plpgsql\src');
-	$plpgsql->AddFiles('src\pl\plpgsql\src', 'gram.y');
+	$plpgsql->AddFiles('src\pl\plpgsql\src', 'pl_gram.y');
 	$plpgsql->AddReference($postgres);
 
 	if ($solution->{options}->{perl})