style: avoid %{...%} in our parser

* src/parse-gram.y (%{...%}): Split in %code and %code requires.
* src/location.h: Add missing includes for self containedness.

src/location.h

@@ -20,6 +20,10 @@
 #ifndef LOCATION_H_
 # define LOCATION_H_
 
+# include <stdbool.h>
+# include <stdio.h>
+# include <string.h> /* strcmp */
+
 # include "uniqstr.h"
 
 /* A boundary between two characters.  */

src/parse-gram.y

@@ -1,4 +1,4 @@
-%{/* Bison Grammar Parser                             -*- C -*-
+/* Bison Grammar Parser                             -*- C -*-
 
    Copyright (C) 2002-2013 Free Software Foundation, Inc.
 
@@ -17,6 +17,14 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
+%code requires
+{
+  #include "symlist.h"
+  #include "symtab.h"
+}
+
+%code
+{
   #include <config.h>
   #include "system.h"
 
@@ -29,15 +37,10 @@
   #include "named-ref.h"
   #include "quotearg.h"
   #include "reader.h"
-#include "symlist.h"
-#include "symtab.h"
   #include "scan-gram.h"
   #include "scan-code.h"
   #include "xmemdup0.h"
-%}
 
-%code
-{
   static int current_prec = 0;
   static location current_lhs_location;
   static named_ref *current_lhs_named_ref;