gitignore: Add m4 directory, libtool and *.swp files

Change-Id: I1ea7a5fce49ea4c398741412094e642d092cdb7b
Signed-off-by: Cyril Bur <cyril.bur@au1.ibm.com>
diff --git a/.gitignore b/.gitignore
index ae85881..75b5f88 100644
--- a/.gitignore
+++ b/.gitignore
@@ -36,6 +36,9 @@
 /texinfo.tex
 
 # Repo Specific Items
+/m4/*
+*.swp
+/libtool
 /*.o
 /config.h
 /config.h.in~