aarch64, Darwin: Account for UNSPEC_SALT_ADDR in symbol output.

We were omitting the postfix relocation indicator because the
code was falling back to the default output when a symbol was
wrapped in an unspec SALT_ADDR.

fixes issue #54.

Signed-off-by: Iain Sandoe <iain@sandoe.co.uk>

gcc/config/aarch64/aarch64.cc

@@ -11921,6 +11921,13 @@ output_macho_postfix_expr (FILE *file, rtx x, const char *postfix)
       output_addr_const (file, XEXP (x, 0));
       break;
 
+    case  UNSPEC:
+      if (XINT (x, 1) == UNSPEC_SALT_ADDR)
+	{
+	  output_macho_postfix_expr (file, XVECEXP (x, 0, 0), postfix);
+	  break;
+	}
+      /* FALLTHROUGH */
     default:
       if (targetm.asm_out.output_addr_const_extra (file, x))
 	break;