init: it is not needed to check DISPLAY environmental variable on mac os x

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@57536 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/init/grass.py

@@ -521,7 +521,7 @@ MAPSET: <UNKNOWN>
 def check_gui():
     global grass_gui, wxpython_base
     # Check if we are running X windows by checking the DISPLAY variable
-    if os.getenv('DISPLAY') or windows:
+    if os.getenv('DISPLAY') or windows or macosx:
         # Check if python is working properly
         if grass_gui == 'wxpython':
             nul = open(os.devnull, 'w')