Mercurial:  ignore precompiled header files on Windows.
diff --git a/.hgignore b/.hgignore
index e27971b..18ccfb5 100644
--- a/.hgignore
+++ b/.hgignore
@@ -86,6 +86,7 @@
 PCbuild/Win32-temp-*
 PCbuild/x64-temp-*
 PCbuild/amd64
+PCbuild/ipch
 BuildLog.htm
 __pycache__
 Modules/_freeze_importlib