[gtk+/gtk-3-22] levelbar: Don't allocate 0 blocks

[Daniel Boles <dboles src gnome org>]

commit 3380cd63c17ea5cf4b279c5c7a334e5b6da4e1e8
Author: Timm Bäder <mail baedert org>
Date:   Sun Apr 30 20:19:56 2017 +0200

    levelbar: Don't allocate 0 blocks
    
    Could result in a division by zero later on and doesn't make a lot of
    sense anyway.

 gtk/gtklevelbar.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtklevelbar.c b/gtk/gtklevelbar.c
index 0e2623f..7fc1279 100644
--- a/gtk/gtklevelbar.c
+++ b/gtk/gtklevelbar.c
@@ -508,6 +508,9 @@ gtk_level_bar_allocate_trough_discrete (GtkLevelBar *self,
   gtk_level_bar_get_min_block_size (self, &block_width, &block_height);
   num_blocks = gtk_level_bar_get_num_blocks (self);
 
+  if (num_blocks == 0)
+    return;
+
   if (self->priv->orientation == GTK_ORIENTATION_HORIZONTAL)
     {
       block_width = MAX (block_width, (gint) floor (allocation->width / num_blocks));