Index: src/lexer.l
--- src/lexer.l.orig
+++ src/lexer.l
@@ -23,7 +23,7 @@
 #define YY_NO_UNPUT
 typedef struct { unsigned int line; off_t off; off_t next; } loc_t;
 #define YYLTYPE loc_t
-#define YY_DECL int yylex YY_PROTO((void))
+#define YY_DECL int yylex (void)
 
 #include <delta.h>
 #include <keyword.h>
@@ -32,8 +32,8 @@ typedef struct { unsigned int line; off_t off; off_t n
 
 #include <parser.h>
 
-YYSTYPE yylval;
-YYLTYPE yylloc;
+extern YYSTYPE yylval;
+extern YYLTYPE yylloc;
 
 %}