auto generated notice

meta.c

@@ -73,6 +73,8 @@ int main() {
         {"RSHIFT",            ">>"},
     };
 
+    printf("// auto generated by meta.c\n");
+
     printf("typedef enum {\n");
     for (int i = 0; i < ilen(kinds); i += 1) {
         printf("    TOK_%s,\n", kinds[i].name);

meta_gen.c

@@ -1,3 +1,4 @@
+// auto generated by meta.c
 typedef enum {
     TOK_EOF,
     TOK_ERROR,