Add search domain to dns interface data.

This doesn't currently use this info - it's still using the system
property based data-passing.  That change is comming.

bug:6799630
Change-Id: I725463209855447cd04bf1457281f3084fffd692
diff --git a/libc/netbsd/resolv/res_cache.c b/libc/netbsd/resolv/res_cache.c
index 838e084..915fdf0 100644
--- a/libc/netbsd/resolv/res_cache.c
+++ b/libc/netbsd/resolv/res_cache.c
@@ -1197,6 +1197,7 @@
     struct resolv_cache_info*   next;
     char*                       nameservers[MAXNS +1];
     struct addrinfo*            nsaddrinfo[MAXNS + 1];
+    char*                       domains;
 } CacheInfo;
 
 #define  HTABLE_VALID(x)  ((x) != NULL && (x) != HTABLE_DELETED)
@@ -1989,7 +1990,8 @@
 }
 
 void
-_resolv_set_nameservers_for_iface(const char* ifname, char** servers, int numservers)
+_resolv_set_nameservers_for_iface(const char* ifname, char** servers, int numservers,
+        const char *domains)
 {
     int i, rt, index;
     struct addrinfo hints;
@@ -2023,6 +2025,7 @@
                 cache_info->nsaddrinfo[index] = NULL;
             }
         }
+        cache_info->domains = strdup(domains);
     }
     pthread_mutex_unlock(&_res_cache_list_lock);
 }
diff --git a/libc/private/resolv_iface.h b/libc/private/resolv_iface.h
index f562687..3fe586e 100644
--- a/libc/private/resolv_iface.h
+++ b/libc/private/resolv_iface.h
@@ -48,7 +48,8 @@
 extern void _resolv_set_default_iface(const char* ifname);
 
 /* set name servers for an interface */
-extern void _resolv_set_nameservers_for_iface(const char* ifname, char** servers, int numservers);
+extern void _resolv_set_nameservers_for_iface(const char* ifname, char** servers, int numservers,
+        const char *domains);
 
 /* tell resolver of the address of an interface */
 extern void _resolv_set_addr_of_iface(const char* ifname, struct in_addr* addr);