diff --git a/include/exterr.h b/include/exterr.h
--- a/include/exterr.h
+++ b/include/exterr.h
@@ -11,8 +11,7 @@
 #ifndef _EXTERR_H_
 #define	_EXTERR_H_
 
-#include <sys/cdefs.h>
-#include <sys/exterr_cat.h>
+#include <sys/types.h>
 
 __BEGIN_DECLS
 int uexterr_gettext(char *buf, size_t bufsz);
diff --git a/lib/libc/gen/uexterr_format.c b/lib/libc/gen/uexterr_format.c
--- a/lib/libc/gen/uexterr_format.c
+++ b/lib/libc/gen/uexterr_format.c
@@ -9,6 +9,7 @@
  */
 
 #include <sys/param.h>
+#include <sys/exterr_cat.h>
 #include <sys/exterrvar.h>
 #include <exterr.h>
 #include <stdbool.h>