Fixed IP interface enumeration Linux to work with IPv6 (see ticket #415)

git-svn-id: https://svn.pjsip.org/repos/pjproject/trunk@1612 74dad513-b988-da41-8d7b-12977e46ad98
diff --git a/aconfigure.ac b/aconfigure.ac
index 684bac1..7af9b49 100644
--- a/aconfigure.ac
+++ b/aconfigure.ac
@@ -144,6 +144,7 @@
 AC_CHECK_HEADER(netinet/in.h,[AC_DEFINE(PJ_HAS_NETINET_IN_H,1)])
 AC_CHECK_HEADER(netinet/ip.h,[AC_DEFINE(PJ_HAS_NETINET_IP_H,1)])
 AC_CHECK_HEADER(net/if.h,[AC_DEFINE(PJ_HAS_NET_IF_H,1)])
+AC_CHECK_HEADER(ifaddrs.h,[AC_DEFINE(PJ_HAS_IFADDRS_H,1)])
 AC_CHECK_HEADER(setjmp.h,[AC_DEFINE(PJ_HAS_SETJMP_H,1)])
 AC_CHECK_HEADER(stdarg.h,[AC_DEFINE(PJ_HAS_STDARG_H,1)])
 AC_CHECK_HEADER(stddef.h,[AC_DEFINE(PJ_HAS_STDDEF_H,1)])