include/stdbit.h
@@ -1,5 +1,5 @@
 /*-
- * Copyright (c) 2025 Robert Clausecker <fuz@FreeBSD.org>
+ * Copyright (c) 2025-2026 Robert Clausecker <fuz@FreeBSD.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -8,6 +8,26 @@
 #define __STDC_VERSION_STDBIT_H__ 202311L
 
 #include <sys/cdefs.h>
+#include <sys/_types.h>
+#include <sys/_stdint.h>
+
+#ifndef _SIZE_T_DECLARED
+typedef __size_t	size_t;
+#define _SIZE_T_DECLARED
+#endif
+
+#ifndef _INT_LEAST_T_DECLARED
+typedef	__int_least8_t		int_least8_t;
+typedef	__int_least16_t		int_least16_t;
+typedef	__int_least32_t		int_least32_t;
+typedef	__int_least64_t		int_least64_t;
+
+typedef	__uint_least8_t		uint_least8_t;
+typedef	__uint_least16_t	uint_least16_t;
+typedef	__uint_least32_t	uint_least32_t;
+typedef	__uint_least64_t	uint_least64_t;
+#define _INT_LEAST_T_DECLARED
+#endif
 
 /* byte order */
 #define  __STDC_ENDIAN_LITTLE__ __ORDER_LITTLE_ENDIAN__
diff --git a/sys/sys/stdint.h b/sys/sys/stdint.h
index 77f469f3c2a3..dccc5a8e6a6d 100644
--- a/sys/sys/stdint.h
+++ b/sys/sys/stdint.h
@@ -35,6 +35,7 @@
 #include <machine/_stdint.h>
 #include <sys/_stdint.h>
 
+#ifndef _INT_LEAST_T_DECLARED
 typedef	__int_least8_t		int_least8_t;
 typedef	__int_least16_t		int_least16_t;
 typedef	__int_least32_t		int_least32_t;
@@ -44,6 +45,8 @@ typedef	__uint_least8_t		uint_least8_t;
 typedef	__uint_least16_t	uint_least16_t;
 typedef	__uint_least32_t	uint_least32_t;
 typedef	__uint_least64_t	uint_least64_t;
+#define _INT_LEAST_T_DECLARED
+#endif
 
 typedef	__int_fast8_t		int_fast8_t;
 typedef	__int_fast16_t		int_fast16_t;