diff --git a/libobjc/ChangeLog b/libobjc/ChangeLog
index ef554a7f6a8..619683259e8 100644
--- a/libobjc/ChangeLog
+++ b/libobjc/ChangeLog
@@ -1,3 +1,8 @@
+2004-06-21  Nick Clifton  <nickc@redhat.com>
+
+	* encoding.c (BITS_PER_UNIT): Define if a definition is not
+	provided.
+
 2004-06-20  Alexander Malmberg  <alexander@malmberg.org>
 
         * Makefile.in (exception.lo): Remove $(OBJC_GCFLAGS).
diff --git a/libobjc/encoding.c b/libobjc/encoding.c
index 4d45b4423df..248ab10bd9a 100644
--- a/libobjc/encoding.c
+++ b/libobjc/encoding.c
@@ -79,7 +79,10 @@ Boston, MA 02111-1307, USA.  */
 /* Some ports (eg ARM) allow the structure size boundary to be
    selected at compile-time.  We override the normal definition with
    one that has a constant value for this compilation.  */
-#undef STRUCTURE_SIZE_BOUNDARY
+#ifndef BITS_PER_UNIT
+#define BITS_PER_UNIT 8
+#endif
+#undef  STRUCTURE_SIZE_BOUNDARY
 #define STRUCTURE_SIZE_BOUNDARY (BITS_PER_UNIT * sizeof (struct{char a;}))
 
 /* Some ROUND_TYPE_ALIGN macros use TARGET_foo, and consequently