Index: include/Makefile
===================================================================
--- include/Makefile
+++ include/Makefile
@@ -12,8 +12,8 @@
 SUBDIR_PARALLEL=
 INCS=	a.out.h ar.h assert.h bitstring.h complex.h cpio.h _ctype.h ctype.h \
 	db.h \
-	dirent.h dlfcn.h elf.h elf-hints.h err.h fmtmsg.h fnmatch.h fstab.h \
-	fts.h ftw.h getopt.h glob.h grp.h \
+	dirent.h dlfcn.h elf.h elf-hints.h endian.h err.h fmtmsg.h fnmatch.h \
+	fstab.h fts.h ftw.h getopt.h glob.h grp.h \
 	ieeefp.h ifaddrs.h \
 	inttypes.h iso646.h kenv.h langinfo.h libgen.h limits.h link.h \
 	locale.h malloc.h malloc_np.h memory.h monetary.h mpool.h mqueue.h \
Index: include/endian.h
===================================================================
--- /dev/null
+++ include/endian.h
@@ -0,0 +1,48 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2019 The FreeBSD Foundation
+ *
+ * This software was developed by Mark Johnston under sponsorship from
+ * the FreeBSD Foundation.
+ *
+ * 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 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 AUTHOR 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.
+ */
+
+#ifndef _ENDIAN_H_
+#define	_ENDIAN_H_
+
+#include <sys/endian.h>
+
+/*
+ * Avoid polluting the namespace.  Consumers can include sys/endian.h
+ * directly if they want the bswap*() macros.
+ */
+#undef bswap16
+#undef bswap32
+#undef bswap64
+
+#define	__BYTE_ORDER	_BYTE_ORDER
+#define	__BIG_ENDIAN	_BIG_ENDIAN
+#define	__LITTLE_ENDIAN	_LITTLE_ENDIAN
+
+#endif
Index: sys/sys/endian.h
===================================================================
--- sys/sys/endian.h
+++ sys/sys/endian.h
@@ -67,16 +67,16 @@
  * endian to host byte order functions as detailed in byteorder(9).
  */
 #if _BYTE_ORDER == _LITTLE_ENDIAN
-#define	htobe16(x)	bswap16((x))
-#define	htobe32(x)	bswap32((x))
-#define	htobe64(x)	bswap64((x))
+#define	htobe16(x)	__bswap16((x))
+#define	htobe32(x)	__bswap32((x))
+#define	htobe64(x)	__bswap64((x))
 #define	htole16(x)	((uint16_t)(x))
 #define	htole32(x)	((uint32_t)(x))
 #define	htole64(x)	((uint64_t)(x))
 
-#define	be16toh(x)	bswap16((x))
-#define	be32toh(x)	bswap32((x))
-#define	be64toh(x)	bswap64((x))
+#define	be16toh(x)	__bswap16((x))
+#define	be32toh(x)	__bswap32((x))
+#define	be64toh(x)	__bswap64((x))
 #define	le16toh(x)	((uint16_t)(x))
 #define	le32toh(x)	((uint32_t)(x))
 #define	le64toh(x)	((uint64_t)(x))
@@ -84,16 +84,16 @@
 #define	htobe16(x)	((uint16_t)(x))
 #define	htobe32(x)	((uint32_t)(x))
 #define	htobe64(x)	((uint64_t)(x))
-#define	htole16(x)	bswap16((x))
-#define	htole32(x)	bswap32((x))
-#define	htole64(x)	bswap64((x))
+#define	htole16(x)	__bswap16((x))
+#define	htole32(x)	__bswap32((x))
+#define	htole64(x)	__bswap64((x))
 
 #define	be16toh(x)	((uint16_t)(x))
 #define	be32toh(x)	((uint32_t)(x))
 #define	be64toh(x)	((uint64_t)(x))
-#define	le16toh(x)	bswap16((x))
-#define	le32toh(x)	bswap32((x))
-#define	le64toh(x)	bswap64((x))
+#define	le16toh(x)	__bswap16((x))
+#define	le32toh(x)	__bswap32((x))
+#define	le64toh(x)	__bswap64((x))
 #endif /* _BYTE_ORDER == _LITTLE_ENDIAN */
 
 /* Alignment-agnostic encode/decode bytestream to/from little/big endian. */