- Issue #13150, #17512: sysconfig no longer parses the Makefile and config.h
  files when imported, instead doing it at build time.  This makes importing
  sysconfig faster and reduces Python startup time by 20%.
diff --git a/.hgignore b/.hgignore
index de9bd5d..c51c53c 100644
--- a/.hgignore
+++ b/.hgignore
@@ -35,6 +35,7 @@
 Parser/pgen.stamp$
 ^core
 ^python-gdb.py
+^pybuilddir.txt
 
 syntax: glob
 python.exe-gdb.py