Log Message:
vala: update to 0.56.14.

Vala 0.56.14
============
 * Various improvements and bug fixes:
  - codegen: Generate compatible wrapper of ref-void functions [#1486]
  - vala: Prevent usage of strlen() on non-null-terminated string [#1485]

 * Bindings:
  - glib-2.0: Add new symbols from 2.78
  - gstreamer-1.0: Make ElementFactory.make()'s name parameter default to null
  - gtk4-wayland: Add the missing wayland-client bindings
  - wayland-client: Complete the binding