vma-iter: Port to 64-bit Haiku

[Bruno Haible]

On Haiku/x86_64 the call to get_next_area_info emits a warning, because
the signature of this function has changed. This patch fixes it.


2021-01-16  Bruno Haible  <bruno@clisp.org>

        vma-iter: Port to 64-bit Haiku.
        * lib/vma-iter.c (vma_iterate): Adapt to changed signature of
        get_next_area_info.

diff --git a/lib/vma-iter.c b/lib/vma-iter.c
index f3bfec4..809828b 100644
--- a/lib/vma-iter.c
+++ b/lib/vma-iter.c
@@ -1459,7 +1459,7 @@ vma_iterate (vma_iterate_callback_fn callback, void *data)
   /* Use the BeOS specific API.  */
 
   area_info info;
-  int32 cookie;
+  ssize_t cookie;
 
   cookie = 0;
   while (get_next_area_info (0, &cookie, &info) == B_OK)