Fix to be complied with multiple C libraries

Avoid in6_addr redefinition

in6_addr is defined both in <linux/in6.h> and in <netinet/in.h>
therefore in6_addr is being redefined. Remove the include <linux/in6.h>
from <linux/if_bridge.h>

Update to be a C project

v0.2

Update to be a C project

Initial release

v0.1

Updated after review