--- a/mercurial/match.py	Tue Mar 14 13:10:30 2017 -0700
+++ b/mercurial/match.py	Wed Mar 15 14:51:18 2017 +0530
@@ -742,7 +742,7 @@
     syntax = 'relre:'
     patterns = []
 
-    fp = open(filepath)
+    fp = open(filepath, 'rb')
     for lineno, line in enumerate(util.iterfile(fp), start=1):
         if "#" in line:
             global _commentre