diff --git a/configure.in b/configure.in
index 50752d2da..d15fd8454 100644
--- a/configure.in
+++ b/configure.in
@@ -46,7 +46,7 @@ dnl Checks for header files.
 AC_HEADER_STDC
 
 AC_CHECK_HEADERS(arpa/inet.h crypt.h db.h dbm.h fcntl.h grp.h)
-AC_CHECK_HEADERS(limits.h ndbm.h netdb.h netinet/in.h paths.h pwd.h)
+AC_CHECK_HEADERS(limits.h ndbm.h netdb.h netinet/in.h netinet/in6_machtypes.h paths.h pwd.h)
 AC_CHECK_HEADERS(rpcsvc/dbm.h shadow.h sys/bitypes.h sys/filio.h)
 AC_CHECK_HEADERS(sys/ioctl.h sys/param.h sys/proc.h sys/resource.h)
 AC_CHECK_HEADERS(sys/socket.h sys/stat.h sys/sysctl.h sys/time.h)
diff --git a/lib/gssapi/gssapi.h b/lib/gssapi/gssapi.h
index 23f155aa9..32164db42 100644
--- a/lib/gssapi/gssapi.h
+++ b/lib/gssapi/gssapi.h
@@ -14,6 +14,10 @@
 
 #include <sys/types.h>
 
+#ifdef HAVE_NETINET_IN6_MACHTYPES_H
+#include <netinet/in6_machtypes.h>
+#endif
+
 #ifdef HAVE_SYS_BITYPES_H
 #include <sys/bitypes.h>
 #endif
diff --git a/lib/gssapi/krb5/gssapi.h b/lib/gssapi/krb5/gssapi.h
index 23f155aa9..32164db42 100644
--- a/lib/gssapi/krb5/gssapi.h
+++ b/lib/gssapi/krb5/gssapi.h
@@ -14,6 +14,10 @@
 
 #include <sys/types.h>
 
+#ifdef HAVE_NETINET_IN6_MACHTYPES_H
+#include <netinet/in6_machtypes.h>
+#endif
+
 #ifdef HAVE_SYS_BITYPES_H
 #include <sys/bitypes.h>
 #endif
diff --git a/lib/krb5/krb5.h b/lib/krb5/krb5.h
index 124fddf93..f7b844224 100644
--- a/lib/krb5/krb5.h
+++ b/lib/krb5/krb5.h
@@ -11,6 +11,10 @@
 #include <config.h>
 #endif
 
+#ifdef HAVE_NETINET_IN6_MACHTYPES_H
+#include <netinet/in6_machtypes.h>
+#endif
+
 #ifdef HAVE_SYS_BITYPES_H
 #include <sys/bitypes.h>
 #endif