Detect asprintf's ENOMEM in procfs.c rather than everywhere

* procfs.h: Make CONTENTS_LEN an ssize_t rather than a size_t,
  and document the change.
* procfs.c (procfs_get_contents): Initialize CONTENTS_LEN to a
  negative value, and fail with ENOMEM if it's still negative after the
  callback returns.  (everywhere): Update to ssize_t.
* dircat.c, netfs.c, process.c,
  procfs_dir.c, proclist.c, rootdir.c: Update to
  ssize_t and the new GET_CONTENTS semantics.

1 files changed, 1 insertions, 1 deletions

diff --git a/procfs_dir.c b/procfs_dir.c
index 4df46695..8ec3f7a5 100644
--- a/procfs_dir.c
+++ b/procfs_dir.c
@@ -11,7 +11,7 @@ struct procfs_dir_node
 };
 
 static error_t
-procfs_dir_get_contents (void *hook, char **contents, size_t *contents_len)
+procfs_dir_get_contents (void *hook, char **contents, ssize_t *contents_len)
 {
   static const char dot_dotdot[] = ".\0..";
   struct procfs_dir_node *dn = hook;