Update the resolver in libc to BIND9's one.

Since, res_sendsigned(3) and the friends use MD5 functions, it is
hard to include them without having MD5 functions in libc.  So,
res_sendsigned(3) is not merged into libc.

Since, res_update(3) in BIND9 is not binary compatible with our
res_update(3), res_update(3) is leaved as is, except some
necessary modifications.
The res_update(3) and the friends are not essential part of the
resolver.  They are not defined in resolv.h but defined in
res_update.h separately in BIND9.  Further, they are not called from
our tree.  So, I hide them from our resolv.h, but leave them only
for binary backward compatibility (perhaps, no one calls them).

Since, struct __res_state_ext is not exposed in BIND9, I hide it
from our resolv.h.  And, global variable _res_ext is removed.  It
breaks binary backward compatibility.  But, since it is not used from
outside of our libc, I think it is safe.

Reviewed by:	arch@ (no objection)

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/libc/net/netdb_private.h b/lib/libc/net/netdb_private.h
index 0b32780..cbdcb17 100644
--- a/lib/libc/net/netdb_private.h
+++ b/lib/libc/net/netdb_private.h
@@ -36,6 +36,8 @@
 #define	_HOSTBUFSIZE	(8 * 1024)
 #define	_NETBUFSIZE	1025
 
+struct __res_state;
+
 struct hostent_data {
 	uint32_t host_addr[4];			/* IPv4 or IPv6 */
 	char *h_addr_ptrs[_MAXADDRS + 1];
@@ -43,6 +45,7 @@ struct hostent_data {
 	char hostbuf[_HOSTBUFSIZE];
 	FILE *hostf;
 	int stayopen;
+	struct __res_state *res;
 #ifdef YP
 	char *yp_domain;
 #endif