--- a/include/libbb.h
+++ b/include/libbb.h
@@ -35,6 +35,7 @@
 #include <sys/poll.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
+#include <sys/resource.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/time.h>
