[sfnt] Ignore embedded bitmaps with zero size (#46379).

* src/sfnt/ttsbit.c (tt_sbit_decoder_load_bit_aligned): Implement
it.

ChangeLog

@@ -1,3 +1,10 @@
+2015-11-05  Werner Lemberg  <wl@gnu.org>
+
+	[sfnt] Ignore embedded bitmaps with zero size (#46379).
+
+	* src/sfnt/ttsbit.c (tt_sbit_decoder_load_bit_aligned): Implement
+	it.
+
 2015-11-04  Werner Lemberg  <wl@gnu.org>
 
 	[truetype] Catch infinite recursion in subglyphs (#46372).

src/sfnt/ttsbit.c

@@ -808,6 +808,12 @@
       goto Exit;
     }
 
+    if ( !line_bits || !height )
+    {
+      /* nothing to do */
+      goto Exit;
+    }
+
     /* now do the blit */
 
     /* adjust `line' to point to the first byte of the bitmap */