diff --git a/lib/linguist/vendor.yml b/lib/linguist/vendor.yml
index ed89eda8..7b7b75f8 100644
--- a/lib/linguist/vendor.yml
+++ b/lib/linguist/vendor.yml
@@ -20,10 +20,16 @@
 - ^deps/
 - ^tools/
 - (^|/)configure$
-- (^|/)configure.ac$
 - (^|/)config.guess$
 - (^|/)config.sub$
 
+# stuff autogenerated by autoconf - still C deps
+- (^|/)libtool.m4
+- (^|/)ltoptions.m4
+- (^|/)ltsugar.m4
+- (^|/)ltversion.m4
+- (^|/)lt~obsolete.m4
+
 # Linters
 - cpplint.py