Log Message:
vala: updated to 0.56.17

Vala 0.56.17
============
 * Various improvements and bug fixes:
  - codegen:
    + Add missing initializers for private fields of GSourceFuncs
    + Update array length variable passed to null-terminated ref parameter
    + Properly pass through a null-terminated out argument
    + Refactor and cache parameter in loop
    + Only handle null-terminated array as such if there is no length given
  - vala:
    + Allow declaration of static nested methods (local functions)
    + Correctly use Path.build_path()
    + Point to the invalid initializer on error
    + Report invalid type in property assignment attempt
    + Inherit important attributes for Property backing field

 * Bindings:
  - glib-2.0: Avoid unnecessary copying operations in FileStream.read_line()
  - glib-2.0: Add SPACING_MARK, deprecate COMBINING_MARK
  - glib-2.0: Add dev_t/gid_t/pid_t/uid_t/socklen_t types for compatibility
  - gnu: add binding for flock(2) and its constants