gencgc: i in add_new_area needs to be signed

  Regression from 7be8d1462a207bda809cd7553c5d76c6ebc4dda2,
  broke finalize.test.sh on x86 builds.

  Fixes lp#989958.

diff --git a/src/runtime/gencgc.c b/src/runtime/gencgc.c
index f0b9c13..6decdde 100644 (file)
--- a/src/runtime/gencgc.c
+++ b/src/runtime/gencgc.c
@@ -917,7 +917,8 @@ size_t max_new_areas;
 static void
 add_new_area(page_index_t first_page, size_t offset, size_t size)
 {
-    size_t new_area_start, c, i;
+    size_t new_area_start, c;
+    ssize_t i;
 
     /* Ignore if full. */
     if (new_areas_index >= NUM_NEW_AREAS)