gdk/win32: Fix modifiers sometimes being consumed for special keys

Windows keymaps contain some bogus mappings, e.g. Ctrl+Backspace=Delete.
Previously, we correctly identified the key as Backspace, but the Ctrl
was still consumed, so the Ctrl+Backspace keybinding did not work.

gdk/win32/gdkkeys-win32-impl.c

@@ -256,6 +256,12 @@ vk_to_char_fuzzy (GdkWin32KeymapLayoutInfo *info,
   int                n_levels;
   int                entry_size;
 
+  /* Initialize with defaults */
+  if (consumed_mod_bits)
+    *consumed_mod_bits = 0;
+  if (is_dead)
+    *is_dead = FALSE;
+
   g_return_val_if_fail (tables != NULL, WCH_NONE);
 
   wch_tables = tables->pVkToWcharTable.ptr;