st/egl: Add GDI backend.
The backend uses Windows GDI driver to provide a software EGL
implementation on Windows.
diff --git a/src/gallium/SConscript b/src/gallium/SConscript
index e5e9578..f47907e 100644
--- a/src/gallium/SConscript
+++ b/src/gallium/SConscript
@@ -15,6 +15,7 @@
SConscript('state_trackers/glx/xlib/SConscript')
SConscript('state_trackers/dri/SConscript')
SConscript('state_trackers/xorg/SConscript')
+ SConscript('state_trackers/egl/SConscript')
if platform == 'windows':
SConscript('state_trackers/wgl/SConscript')