Index: tools/hook-scripts/mailer/mailer.py
===================================================================
--- tools/hook-scripts/mailer/mailer.py	(revision 1438886)
+++ tools/hook-scripts/mailer/mailer.py	(working copy)
@@ -144,6 +144,11 @@ class OutputBase:
 
   def make_subject(self, group, params):
     prefix = self.cfg.get(self.prefix_param, group, params)
+
+    if prefix and re.search(r'REPONAME', prefix):
+        reponame = os.path.basename(os.path.dirname(os.path.dirname(__file__)))
+        prefix = re.sub(r'REPONAME', reponame, prefix)
+
     if prefix:
       subject = prefix + ' ' + self.subject
     else: