--- /dev/null
+++ Libc/Libc-1725.40.4/include/struct.h
@@ -0,0 +1,79 @@
+/*-
+ * Copyright (c) 1983, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)struct.h	8.1 (Berkeley) 6/2/93
+ */
+
+#ifndef _STRUCT_H_
+#define	_STRUCT_H_
+
+/* Offset of the field in the structure. */
+#define	fldoff(name, field) \
+	((int)&(((struct name *)0)->field))
+
+/* Size of the field in the structure. */
+#define	fldsiz(name, field) \
+	(sizeof(((struct name *)0)->field))
+
+/* Address of the structure from a field. */
+#define	strbase(name, addr, field) \
+	((struct name *)((char *)(addr) - fldoff(name, field)))
+
+/*
+ * countof() cannot be safely used in a _Static_assert statement, so we provide
+ * an unsafe variant that does not verify the input array is statically-defined.
+ */
+#define countof_unsafe(arr) \
+	(sizeof(arr) / sizeof(arr[0]))
+
+/* Number of elements in a statically-defined array */
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L && __GNUC__
+#define countof(arr) ({ \
+	_Static_assert( \
+			!__builtin_types_compatible_p(typeof(arr), typeof(&(arr)[0])), \
+			"array must be statically defined"); \
+	(sizeof(arr) / sizeof(arr[0])); \
+})
+#else
+#define countof(arr) \
+	countof_unsafe(arr)
+#endif
+
+/* Length of a statically-defined string (does not include null terminator) */
+#define lenof(str) \
+	(sizeof(str) - 1)
+
+/* Last index of a statically-defined array */
+#define lastof(arr) \
+	(countof(arr) - 1)
+
+#endif /* !_STRUCT_H_ */