Fix compilation with modern C: add correct function declarations
https://bugs.gentoo.org/883893
https://bugs.gentoo.org/930372
https://bugs.gentoo.org/932280
--- a/xshogi/parser.y
+++ b/xshogi/parser.y
@@ -70,7 +70,9 @@
                   
 enum { False, True };
 
-static void yyerror();
+static void yyerror(char *);
+extern int yyparse (void);
+extern int yylex (void);
            
 static ShogiMove move_type;
 static int  from_x, from_y, to_x, to_y;
@@ -88,6 +90,7 @@
 extern void SendToProgram(char *message, FILE *fp);
 extern void MakeMove(ShogiMove *move_type, int from_x, int from_y, 
                      int to_x, int to_y);
+extern void DisplayMessage(char *message, int toRemotePlayer);
 
 %}