[gimp] Issue #4338 Plug-in file-header exporting to format C header wrong output.

[Michael Natterer <mitch src gnome org>]

commit 4b07c62cbcc6ca90119b8f65f4cb51abb60b3c9a
Author: lillolollo <4179-lillolollo users noreply gitlab gnome org>
Date:   Mon Dec 9 06:03:23 2019 +0000

    Issue #4338 Plug-in file-header exporting to format C header wrong output.
    
    (cherry picked from commit 3f76d7782a10185ce60178f5dbf6e288da46bdfa)

 plug-ins/common/file-header.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/plug-ins/common/file-header.c b/plug-ins/common/file-header.c
index 39edebe998..efe6aab296 100644
--- a/plug-ins/common/file-header.c
+++ b/plug-ins/common/file-header.c
@@ -327,7 +327,7 @@ save_image (GFile         *file,
       cmap = gimp_image_get_colormap (image, &colors);
 
       if (! print (output, error,
-                   "static char header_data_cmap[256][3] = {") ||
+                   "static unsigned char header_data_cmap[256][3] = {") ||
           ! print (output, error,
                    "\n\t{%3d,%3d,%3d}",
                    (gint) cmap[0], (gint) cmap[1], (gint) cmap[2]))
@@ -361,7 +361,7 @@ save_image (GFile         *file,
       g_free (cmap);
 
       /* save image */
-      if (! print (output, error, "static char header_data[] = {\n\t"))
+      if (! print (output, error, "static unsigned char header_data[] = {\n\t"))
         goto fail;
 
       data = g_new (guchar, width * 1);