[gimp] plug-ins: in file-psd, fix bad sign extension in decode_packbits()

[N/A <ell src gnome org>]

commit 9e015f4b7de806008866b0c27de4659865ae91a3
Author: Ell <ell_se yahoo com>
Date:   Mon Oct 9 08:39:32 2017 -0400

    plug-ins: in file-psd, fix bad sign extension in decode_packbits()

 plug-ins/file-psd/psd-util.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/plug-ins/file-psd/psd-util.c b/plug-ins/file-psd/psd-util.c
index a42c8ee..aba3108 100644
--- a/plug-ins/file-psd/psd-util.c
+++ b/plug-ins/file-psd/psd-util.c
@@ -497,7 +497,7 @@ decode_packbits (const gchar *src,
 
   while (unpack_left > 0 && pack_left > 0)
     {
-      n = *src;
+      n = *(const guchar *) src;
       src++;
       pack_left--;