auto import from //depot/cupcake/@135843
diff --git a/libc/arch-x86/include/endian.h b/libc/arch-x86/include/endian.h
new file mode 100644
index 0000000..ad37919
--- /dev/null
+++ b/libc/arch-x86/include/endian.h
@@ -0,0 +1,70 @@
+/* $OpenBSD: endian.h,v 1.14 2005/12/13 00:35:23 millert Exp $ */
+
+/*-
+ * Copyright (c) 1997 Niklas Hallqvist. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ */
+
+#ifndef _I386_ENDIAN_H_
+#define _I386_ENDIAN_H_
+
+#ifdef __GNUC__
+
+#if defined(_KERNEL) && !defined(I386_CPU)
+#define __swap32md(x) ({ \
+ u_int32_t __swap32md_x = (x); \
+ \
+ __asm ("bswap %1" : "+r" (__swap32md_x)); \
+ __swap32md_x; \
+})
+#else
+#define __swap32md(x) ({ \
+ u_int32_t __swap32md_x = (x); \
+ \
+ __asm ("rorw $8, %w1; rorl $16, %1; rorw $8, %w1" : \
+ "+r" (__swap32md_x)); \
+ __swap32md_x; \
+})
+#endif /* _KERNEL && !I386_CPU */
+
+#define __swap64md(x) ({ \
+ u_int64_t __swap64md_x = (x); \
+ \
+ (u_int64_t)__swap32md(__swap64md_x >> 32) | \
+ (u_int64_t)__swap32md(__swap64md_x & 0xffffffff) << 32; \
+})
+#define __swap16md(x) ({ \
+ u_int16_t __swap16md_x = (x); \
+ \
+ __asm ("rorw $8, %w1" : "+r" (__swap16md_x)); \
+ __swap16md_x; \
+})
+
+/* Tell sys/endian.h we have MD variants of the swap macros. */
+#define MD_SWAP
+
+#endif /* __GNUC__ */
+
+#define _BYTE_ORDER _LITTLE_ENDIAN
+#include <sys/endian.h>
+
+#endif /* _I386_ENDIAN_H_ */