properly free memory in pgen
diff --git a/Parser/pgenmain.c b/Parser/pgenmain.c
index e9d3082..e386248 100644
--- a/Parser/pgenmain.c
+++ b/Parser/pgenmain.c
@@ -80,6 +80,7 @@
         printf("Writing %s ...\n", graminit_h);
     printnonterminals(g, fp);
     fclose(fp);
+    freegrammar(g);
     Py_Exit(0);
     return 0; /* Make gcc -Wall happy */
 }