Stop calling res_init

Emacs shouldn’t need to call res_init any more, now that nscd or
equivalent is everywhere.  On modern systems, calling res_init
simply slows Emacs down.  On ancient systems lacking nscd Emacs
will still work well enough with this change; it’s just that it
won’t respond to changes in /etc/resolv.conf.
* configure.ac (HAVE_RES_INIT): Remove.  Worry about -lresolv only
when configured --with-hesiod.  Hesiod is still used; see, e.g.:
https://soylentnews.org/meta/article.pl?sid=15/07/13/0255214
* src/Makefile.in (LIBRESOLV): Remove.  All uses removed.

1 files changed, 0 insertions, 13 deletions

diff --git a/src/process.c b/src/process.c
index f40e8e53a24..85a4885bbf4 100644
--- a/src/process.c
+++ b/src/process.c
@@ -75,11 +75,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 # include <sys/stropts.h>
 #endif
 
-#ifdef HAVE_RES_INIT
-#include <arpa/nameser.h>
-#include <resolv.h>
-#endif
-
 #ifdef HAVE_UTIL_H
 #include <util.h>
 #endif
@@ -3827,10 +3822,6 @@ usage: (make-network-process &rest ARGS)  */)
       immediate_quit = 1;
       QUIT;
 
-#ifdef HAVE_RES_INIT
-      res_init ();
-#endif
-
       struct addrinfo hints;
       memset (&hints, 0, sizeof hints);
       hints.ai_family = family;
@@ -3910,10 +3901,6 @@ usage: (make-network-process &rest ARGS)  */)
       immediate_quit = 1;
       QUIT;
 
-#ifdef HAVE_RES_INIT
-      res_init ();
-#endif
-
       host_info_ptr = gethostbyname ((const char *) SDATA (host));
       immediate_quit = 0;