scons: Do not build glx and egl on Cygwin.

Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: José Fonseca <jfonseca@vmware.com>
diff --git a/src/gallium/SConscript b/src/gallium/SConscript
index b61eba0..e212ed1 100644
--- a/src/gallium/SConscript
+++ b/src/gallium/SConscript
@@ -58,7 +58,7 @@
 
 if not env['embedded']:
     SConscript('state_trackers/vega/SConscript')
-    if env['platform'] not in ['darwin', 'haiku', 'sunos']:
+    if env['platform'] not in ('cygwin', 'darwin', 'haiku', 'sunos'):
         SConscript('state_trackers/egl/SConscript')
 
     if env['x11']:
@@ -124,7 +124,7 @@
 ])
 
 if not env['embedded']:
-    if env['platform'] not in ['darwin', 'haiku', 'sunos']:
+    if env['platform'] not in ('cygwin', 'darwin', 'haiku', 'sunos'):
         SConscript([
             'targets/egl-static/SConscript'
         ])