diff --git a/mailnews/intl/moz.build b/mailnews/intl/moz.build
index 872a5916e1..9c88da129f 100644
--- a/mailnews/intl/moz.build
+++ b/mailnews/intl/moz.build
@@ -27,7 +27,7 @@ GENERATED_FILES += [
     'charsetalias.properties.h',
 ]
 charsetalias = GENERATED_FILES['charsetalias.properties.h']
-charsetalias.script = TOPSRCDIR + '/mozilla/intl/locale/props2arrays.py'
+charsetalias.script = '../../mozilla/intl/locale/props2arrays.py'
 charsetalias.inputs = ['charsetalias.properties']
 
 FINAL_LIBRARY = 'mail'