diff --git a/include/a.out.h b/include/a.out.h
index 9bfed25a05e1..176b39cb3d54 100644
--- a/include/a.out.h
+++ b/include/a.out.h
@@ -37,6 +37,7 @@
 #define	_AOUT_H_
 
 #include <sys/types.h>
+#include <machine/exec.h>
 #include <sys/imgact_aout.h>
 #include <machine/reloc.h>