declare all types that we may use

diff --git a/include/xbt/xbt_os_time.h b/include/xbt/xbt_os_time.h
index 0b1341a..1af3e60 100644 (file)
--- a/include/xbt/xbt_os_time.h
+++ b/include/xbt/xbt_os_time.h
@@ -10,6 +10,7 @@
 #define _XBT_OS_TIMER_H
 
 #include <xbt/misc.h>           /* XBT_PUBLIC */
+#include <stddef.h>             /* size_t */
 
 /** @brief get time in seconds