.gitignore : Ignore more m4 files.
diff --git a/.gitignore b/.gitignore
index c6f7651..b9a3104 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,6 +25,11 @@
 libtool
 libtool-disable-static
 ltmain.sh
+m4/libtool.m4
+m4/ltoptions.m4
+m4/ltsugar.m4
+m4/ltversion.m4
+m4/lt~obsolete.m4
 missing
 src/flac/flac
 src/libFLAC++/flac++.pc