When Apple converted to UNIX03 support (part of the feature list of 10.5), they

renamed the register fields in the thread state structures.  Support compiling
with either the old or new names, keying off the UNIX03 define (which is what
the 10.5 headers do).

Refs trac:450

This commit was SVN r12285.

The following Trac tickets were found above:
  Ticket 450 --> https://svn.open-mpi.org/trac/ompi/ticket/450

opal/mca/backtrace/darwin/MoreBacktrace/MoreDebugging/MoreBacktrace.c

@@ -105,6 +105,19 @@ First checked in.  This code still has bugs, but I've written enough code that c
 	}
 #endif
 
+/* OMPI CHANGE: This is a total hack, but in OS X 10.5 (Leopard), they
+ * renamed all the registers in the thread state structure if
+ * __DARWIN_UNIX03 is defined.  So adapt. 
+ */
+#if defined(__DARWIN_UNIX03) && __DARWIN_UNIX03
+#define srr0 __srr0
+#define lr   __lr
+#define r1   __r1
+#define eip  __eip
+#define ebp  __ebp
+#define esp  __esp
+#endif
+
 /////////////////////////////////////////////////////////////////
 
 // A new architecture will require substantial changes to this file.