scons: make things work when EXTRAS is not defined.

--HG--
extra : convert_revision : 83562b55ec099e609c64cd42eb47a8481e4e85e7

diff --git a/SConstruct b/SConstruct
index 1f3dfb5bba2f3abbc3e26a8b4d7014c940a5f2e5..a2760c4a407bbe2ae16f655a3f6833f6f1961cd5 100644 (file)
--- a/SConstruct
+++ b/SConstruct
@@ -436,6 +436,8 @@ all_cpu_list.sort()
 default_cpus.sort()
 
 def ExtraPathValidator(key, val, env):
+    if not val:
+        return
     paths = val.split(':')
     for path in paths:
         path = os.path.expanduser(path)