diff --git a/SConstruct b/SConstruct
index 471b34bed..a348901c4 100644
--- a/SConstruct
+++ b/SConstruct
@@ -833,7 +833,7 @@ if not preconfigured:
 
         
         svn_version = call('svnversion')
-        if svn_version == 'exported':
+        if not svn_version == 'exported':
             pattern = r'(\d+)(.*)'
             try:
                 rev = re.match(pattern,svn_version).groups()[0]