diff --git a/contrib/notmuch-deliver/.gitignore b/contrib/notmuch-deliver/.gitignore
index 353d1ed5..6971ef20 100644
--- a/contrib/notmuch-deliver/.gitignore
+++ b/contrib/notmuch-deliver/.gitignore
@@ -38,4 +38,5 @@ gprof*
 m4/libtool.m4
 m4/lt*.m4
 
+maildrop/numlib/config.h
 src/notmuch-deliver