diff --git a/contrib/elftoolchain/brandelf/brandelf.c b/contrib/elftoolchain/brandelf/brandelf.c
index 7cc93f02ca2a..d41b926db014 100644
--- a/contrib/elftoolchain/brandelf/brandelf.c
+++ b/contrib/elftoolchain/brandelf/brandelf.c
@@ -46,6 +46,11 @@
 
 ELFTC_VCSID("$Id: brandelf.c 3440 2016-04-07 14:51:47Z emaste $");
 
+/* Backwards compatability for older FreeBSD releases. */
+#ifndef ELFOSABI_CLOUDABI
+#define ELFOSABI_CLOUDABI 17
+#endif
+
 static int elftype(const char *);
 static const char *iselftype(int);
 static void printelftypes(void);
diff --git a/contrib/elftoolchain/elfcopy/main.c b/contrib/elftoolchain/elfcopy/main.c
index ebc0c92a1c01..89ffab299769 100644
--- a/contrib/elftoolchain/elfcopy/main.c
+++ b/contrib/elftoolchain/elfcopy/main.c
@@ -41,6 +41,11 @@
 
 ELFTC_VCSID("$Id: main.c 3446 2016-05-03 01:31:17Z emaste $");
 
+/* Backwards compatability for older FreeBSD releases. */
+#ifndef ELFOSABI_CLOUDABI
+#define ELFOSABI_CLOUDABI 17
+#endif
+
 enum options
 {
 	ECP_ADD_GNU_DEBUGLINK,
diff --git a/contrib/elftoolchain/readelf/readelf.c b/contrib/elftoolchain/readelf/readelf.c
index ba59275298cf..fcfc75d35f96 100644
--- a/contrib/elftoolchain/readelf/readelf.c
+++ b/contrib/elftoolchain/readelf/readelf.c
@@ -50,6 +50,9 @@
 ELFTC_VCSID("$Id: readelf.c 3469 2016-05-15 23:16:09Z emaste $");
 
 /* Backwards compatability for older FreeBSD releases. */
+#ifndef ELFOSABI_CLOUDABI
+#define ELFOSABI_CLOUDABI 17
+#endif
 #ifndef EM_IAMCU
 #define EM_IAMCU 6
 #endif