libglnx porting: Migrate from GSConsole

To GLnxConsoleRef.  There were some subtleties here, for example we
used to reference `GSConsole` inside the progress changed function,
which at first seems like an ABI hazard, because e.g. rpm-ostree or
xdg-app could still be passing a `GSConsole` instance there.  Luckily,
it turns out to be compatible to just start calling libglnx here.

Another issue was that due to libglnx's use of the cleanup function,
we needed to ensure we always called `ostree_async_progress_finish()`
*before* the cleanup function was invoked.

Closes: #280
Approved by: giuseppe

src/libostree/ostree-repo.c

@@ -27,6 +27,7 @@
 #include <gio/gunixinputstream.h>
 #include <gio/gfiledescriptorbased.h>
 #include "otutil.h"
+#include <glnx-console.h>
 
 #include "ostree-core-private.h"
 #include "ostree-repo-private.h"
@@ -4120,12 +4121,15 @@ ostree_repo_pull_with_options (OstreeRepo             *self,
  * custom status message, or else outstanding fetch progress in bytes/sec,
  * or else outstanding content or metadata writes to the repository in
  * number of objects.
+ *
+ * Compatibility note: this function previously assumed that @user_data
+ * was a pointer to a #GSConsole instance.  This is no longer the case,
+ * and @user_data is ignored.
  **/
 void
 ostree_repo_pull_default_console_progress_changed (OstreeAsyncProgress *progress,
                                                    gpointer             user_data)
 {
-  GSConsole *console = user_data;
   GString *buf;
   g_autofree char *status = NULL;
   guint outstanding_fetches;
@@ -4135,7 +4139,8 @@ ostree_repo_pull_default_console_progress_changed (OstreeAsyncProgress *progress
   guint fetched_delta_parts;
   guint total_delta_parts;
 
-  if (!console)
+  /* Historical note; we used to treat this as a GSConsole instance */
+  if (user_data == NULL)
     return;
 
   buf = g_string_new ("");
@@ -4202,7 +4207,7 @@ ostree_repo_pull_default_console_progress_changed (OstreeAsyncProgress *progress
       g_string_append_printf (buf, "Scanning metadata: %u", n_scanned_metadata);
     }
 
-  gs_console_begin_status_line (console, buf->str, NULL, NULL);
+  glnx_console_text (buf->str);
 
   g_string_free (buf, TRUE);
 }