Keep constructors with priorities

Fixes GCOV builds with gcc7, which uses this.

Signed-off-by: Stewart Smith <[email protected]>

Author: stewartsmith

skiboot.lds.S

@@ -1,4 +1,4 @@
-/* Copyright 2013-2014 IBM Corp.
+/* Copyright 2013-2018 IBM Corp.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -86,6 +86,7 @@ SECTIONS
 	.init : {
 		__ctors_start = .;
 		KEEP(*(.ctors))
+		KEEP(*(SORT(.init_array.*)))
 		KEEP(*(.init_array))
 		__ctors_end = .;
 	}