diff --git a/Makefile.inc1 b/Makefile.inc1
index 5e11cc315bd1..f2443c6e490d 100644
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -632,10 +632,14 @@ _elf2exe=	usr.sbin/elf2exe
 _btxld=	usr.sbin/btxld
 .endif
 
+.if ${TARGET_ARCH} == "sparc64"
+_elf2aout=	usr.bin/elf2aout
+.endif
+
 _xlint=	usr.bin/xlint/lint1 usr.bin/xlint/lint2 usr.bin/xlint/xlint
 
 cross-tools:
-.for _tool in ${_btxld} ${_elf2exe} \
+.for _tool in ${_btxld} ${_elf2aout} ${_elf2exe} \
     gnu/usr.bin/binutils usr.bin/objformat usr.sbin/crunch/crunchide \
     gnu/usr.bin/cc ${_xlint}
 	cd ${.CURDIR}/${_tool}; \
diff --git a/usr.bin/elf2aout/elf2aout.c b/usr.bin/elf2aout/elf2aout.c
index f0878806e859..e35dcd3c7bc4 100644
--- a/usr.bin/elf2aout/elf2aout.c
+++ b/usr.bin/elf2aout/elf2aout.c
@@ -27,9 +27,37 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <sys/types.h>
+#include <sys/param.h>
 #include <sys/elf64.h>
+#if __FreeBSD_version >= 500034
 #include <sys/endian.h>
+#else
+#include <machine/endian.h>
+#if BYTE_ORDER == LITTLE_ENDIAN
+
+#define	bswap16(x) \
+	((x >> 8) | (x << 8))
+
+#define	bswap32(x) \
+	((x >> 24) | ((x >> 8) & 0xff00) | ((x << 8) & 0xff0000) | (x << 24))
+
+#define	bswap64(x) \
+	((x >> 56) | ((x >> 40) & 0xff00) | ((x >> 24) & 0xff0000) | \
+	((x >> 8) & 0xff000000) | ((x << 8) & ((u_int64_t)0xff << 32)) | \
+	((x << 24) & ((u_int64_t)0xff << 40)) | \
+	((x << 40) & ((u_int64_t)0xff << 48)) | ((x << 56)))
+
+#define	be16toh(x)      bswap16((x))
+#define	be32toh(x)      bswap32((x))
+#define	be64toh(x)      bswap64((x))
+#define	htobe32(x)      bswap32((x))
+#else
+#define	be16toh(x)	(x)
+#define	be32toh(x)	(x)
+#define	be64toh(x)	(x)
+#define	htobe32(x)	(x)
+#endif
+#endif
 #include <sys/mman.h>
 #include <sys/stat.h>
 
diff --git a/usr.sbin/elf2aout/elf2aout.c b/usr.sbin/elf2aout/elf2aout.c
index f0878806e859..e35dcd3c7bc4 100644
--- a/usr.sbin/elf2aout/elf2aout.c
+++ b/usr.sbin/elf2aout/elf2aout.c
@@ -27,9 +27,37 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <sys/types.h>
+#include <sys/param.h>
 #include <sys/elf64.h>
+#if __FreeBSD_version >= 500034
 #include <sys/endian.h>
+#else
+#include <machine/endian.h>
+#if BYTE_ORDER == LITTLE_ENDIAN
+
+#define	bswap16(x) \
+	((x >> 8) | (x << 8))
+
+#define	bswap32(x) \
+	((x >> 24) | ((x >> 8) & 0xff00) | ((x << 8) & 0xff0000) | (x << 24))
+
+#define	bswap64(x) \
+	((x >> 56) | ((x >> 40) & 0xff00) | ((x >> 24) & 0xff0000) | \
+	((x >> 8) & 0xff000000) | ((x << 8) & ((u_int64_t)0xff << 32)) | \
+	((x << 24) & ((u_int64_t)0xff << 40)) | \
+	((x << 40) & ((u_int64_t)0xff << 48)) | ((x << 56)))
+
+#define	be16toh(x)      bswap16((x))
+#define	be32toh(x)      bswap32((x))
+#define	be64toh(x)      bswap64((x))
+#define	htobe32(x)      bswap32((x))
+#else
+#define	be16toh(x)	(x)
+#define	be32toh(x)	(x)
+#define	be64toh(x)	(x)
+#define	htobe32(x)	(x)
+#endif
+#endif
 #include <sys/mman.h>
 #include <sys/stat.h>