diff --git a/include/mes/mes.h b/include/mes/mes.h
index 04c9f418..9127ca92 100644
--- a/include/mes/mes.h
+++ b/include/mes/mes.h
@@ -77,12 +77,12 @@ struct scm *g_macros;
 struct scm *g_ports;
 
 /* gc */
-long ARENA_SIZE;
-long MAX_ARENA_SIZE;
-long STACK_SIZE;
-long JAM_SIZE;
-long GC_SAFETY;
-long MAX_STRING;
+size_t ARENA_SIZE;
+size_t MAX_ARENA_SIZE;
+size_t STACK_SIZE;
+size_t JAM_SIZE;
+size_t GC_SAFETY;
+size_t MAX_STRING;
 char *g_arena;
 struct scm *cell_arena;
 struct scm *cell_zero;
diff --git a/src/gc.c b/src/gc.c
index 99a56e14..ff411292 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -1,6 +1,6 @@
 /* -*-comment-start: "//";comment-end:""-*-
  * GNU Mes --- Maxwell Equations of Software
- * Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ * Copyright © 2016,2017,2018,2019,2020,2021 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  *
  * This file is part of GNU Mes.
  *