shell: fix header inclusions

1 files changed, 2 insertions, 0 deletions

diff --git a/shell.h b/shell.h
index 73bd2e4..367ef2e 100644
--- a/shell.h
+++ b/shell.h
@@ -29,6 +29,8 @@
 #ifndef _SHELL_H
 #define _SHELL_H
 
+#include <stddef.h>
+
 typedef void (*shell_fn_t)(int argc, char *argv[]);
 
 struct shell_cmd {