[wing] build: Fix building with Meson 0.39.0

[Patrick Griffis <pgriffis src gnome org>]

commit 0c06dfef06e3dd2af10fab3f7d98c2c336f84753
Author: Patrick Griffis <tingping tingping se>
Date:   Thu Mar 9 15:00:06 2017 -0500

    build: Fix building with Meson 0.39.0
    
    wingtk/gtk-win32#135

 wing/meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/wing/meson.build b/wing/meson.build
index def0174..74855aa 100644
--- a/wing/meson.build
+++ b/wing/meson.build
@@ -43,7 +43,7 @@ wing = shared_library('wing-@0@'.format(wing_api_version),
   link_args: wing_link_args)
 
 # Internal dependency, for tests and benchmarks
-wing_inc = include_directories([ meson.current_source_dir(), meson.current_build_dir(), meson.build_root(), 
meson.source_root() ])
+wing_inc = include_directories([ '.', '..' ])
 wing_dep = declare_dependency(link_with: wing,
                               include_directories: [ wing_inc ],
                               dependencies: platform_deps)