Ignore os-proto.h - it might be a symlink to os/os-XXX.h for some XXX.
diff --git a/.gitignore b/.gitignore
index c04500a..cd44e15 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,6 +16,7 @@
 libpcap.so.*
 libpcap-*.tar.gz
 net
+os-proto.h
 pcap-config
 pcap-filter.manmisc
 pcap-linktype.manmisc