[IA64] get back PT_IA_64_UNWIND program header

Explicitly put the unwind section into its own program-header.  This
used to be unnecessary (probably because binutils did it for us), but
with current binutils (e.g., v2.17.50.20070804) we won't get
the PT_IA_64_UNWIND header without this patch which will break
unwinding in a debugger and simulators such as Ski.

Signed-off-by: David Mosberger-Tang <dmosberger@gmail.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/kernel/vmlinux.lds.S

@@ -21,6 +21,7 @@ PHDRS {
   percpu PT_LOAD;
   data   PT_LOAD;
   note   PT_NOTE;
+  unwind 0x70000001; /* PT_IA_64_UNWIND, but ld doesn't match the name */
 }
 SECTIONS
 {
@@ -103,7 +104,8 @@ SECTIONS
 	  __start_unwind = .;
 	  *(.IA_64.unwind*)
 	  __end_unwind = .;
-	}
+	} :code :unwind
+  code_continues2 : {} : code
 
   RODATA