make: Don't need to distribute libtool.
diff --git a/.gitignore b/.gitignore
index 7e87d32..58ff835 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,6 +24,7 @@
 /ndn-cpp/ndn-cpp-config.h
 /ndn-cpp/stamp-h1
 /aclocal.m4
+/libtool
 *.Po
 .deps
 .dirstamp