diff --git a/libc/private/bsd_sys_param.h b/libc/private/bsd_sys_param.h
index 8c936c4..be5f692 100644
--- a/libc/private/bsd_sys_param.h
+++ b/libc/private/bsd_sys_param.h
@@ -16,6 +16,8 @@
 
 #pragma once
 
+#include <inttypes.h>
+
 /* OpenBSD has these in <sys/param.h>, but "ALIGN" isn't something we want to reserve. */
 #define ALIGNBYTES (sizeof(uintptr_t) - 1)
 #define ALIGN(p) (((uintptr_t)(p) + ALIGNBYTES) & ~ALIGNBYTES)