diff --git a/librb/include/rb_lib.h b/librb/include/rb_lib.h
index c02dff6..17a5b6b 100644
--- a/librb/include/rb_lib.h
+++ b/librb/include/rb_lib.h
@@ -9,6 +9,7 @@
 #include <fcntl.h>
 #include <signal.h>
 #include <ctype.h>
+#include <time.h>
 
 #ifdef __GNUC__
 #undef alloca