Remove configure probe for gethostbyname_r.

It was only used by src/port/getaddrinfo.c, removed by the previous
commit.

Discussion: https://postgr.es/m/CA%2BhUKGJFLPCtAC58EAimF6a6GPw30TU_59FUY%3DGWB_kC%3DJEmVQ%40mail.gmail.com

configure

@@ -11750,13 +11750,12 @@ fi
 
 
 
-for ac_func in strerror_r gethostbyname_r
+for ac_func in strerror_r
 do :
-  as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
-ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
-if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
+  ac_fn_c_check_func "$LINENO" "strerror_r" "ac_cv_func_strerror_r"
+if test "x$ac_cv_func_strerror_r" = xyes; then :
   cat >>confdefs.h <<_ACEOF
-#define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
+#define HAVE_STRERROR_R 1
 _ACEOF
 
 fi
@@ -12431,62 +12430,6 @@ fi
 
 
 if test "$enable_thread_safety" = yes; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing gethostbyname_r" >&5
-$as_echo_n "checking for library containing gethostbyname_r... " >&6; }
-if ${ac_cv_search_gethostbyname_r+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  ac_func_search_save_LIBS=$LIBS
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-/* Override any GCC internal prototype to avoid an error.
-   Use char because int might match the return type of a GCC
-   builtin and then its argument prototype would still apply.  */
-#ifdef __cplusplus
-extern "C"
-#endif
-char gethostbyname_r ();
-int
-main ()
-{
-return gethostbyname_r ();
-  ;
-  return 0;
-}
-_ACEOF
-for ac_lib in '' nsl; do
-  if test -z "$ac_lib"; then
-    ac_res="none required"
-  else
-    ac_res=-l$ac_lib
-    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
-  fi
-  if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_search_gethostbyname_r=$ac_res
-fi
-rm -f core conftest.err conftest.$ac_objext \
-    conftest$ac_exeext
-  if ${ac_cv_search_gethostbyname_r+:} false; then :
-  break
-fi
-done
-if ${ac_cv_search_gethostbyname_r+:} false; then :
-
-else
-  ac_cv_search_gethostbyname_r=no
-fi
-rm conftest.$ac_ext
-LIBS=$ac_func_search_save_LIBS
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_gethostbyname_r" >&5
-$as_echo "$ac_cv_search_gethostbyname_r" >&6; }
-ac_res=$ac_cv_search_gethostbyname_r
-if test "$ac_res" != no; then :
-  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
-
-fi
-
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing pthread_barrier_wait" >&5
 $as_echo_n "checking for library containing pthread_barrier_wait... " >&6; }
 if ${ac_cv_search_pthread_barrier_wait+:} false; then :

configure.ac

@@ -1214,7 +1214,7 @@ LIBS="$LIBS $PTHREAD_LIBS"
 AC_CHECK_HEADER(pthread.h, [], [AC_MSG_ERROR([
 pthread.h not found;  use --disable-thread-safety to disable thread safety])])
 
-AC_CHECK_FUNCS([strerror_r gethostbyname_r])
+AC_CHECK_FUNCS([strerror_r])
 
 # Do test here with the proper thread flags
 PGAC_FUNC_STRERROR_R_INT
@@ -1260,7 +1260,6 @@ AC_SEARCH_LIBS(shmget, cygipc)
 AC_SEARCH_LIBS(backtrace_symbols, execinfo)
 
 if test "$enable_thread_safety" = yes; then
-  AC_SEARCH_LIBS(gethostbyname_r, nsl)
   AC_SEARCH_LIBS(pthread_barrier_wait, pthread)
 fi
 

src/include/pg_config.h.in

@@ -178,9 +178,6 @@
    */
 #undef HAVE_GCC__SYNC_INT64_CAS
 
-/* Define to 1 if you have the `gethostbyname_r' function. */
-#undef HAVE_GETHOSTBYNAME_R
-
 /* Define to 1 if you have the `getifaddrs' function. */
 #undef HAVE_GETIFADDRS
 

src/interfaces/libpq/fe-connect.c

@@ -2229,7 +2229,7 @@ connectDBComplete(PGconn *conn)
  *		will not block.
  *	 o	If you do not supply an IP address for the remote host (i.e. you
  *		supply a host name instead) then PQconnectStart will block on
- *		gethostbyname.  You will be fine if using Unix sockets (i.e. by
+ *		getaddrinfo.  You will be fine if using Unix sockets (i.e. by
  *		supplying neither a host name nor a host address).
  *	 o	If your backend wants to use Kerberos authentication then you must
  *		supply both a host name and a host address, otherwise this function

src/tools/msvc/Solution.pm

@@ -256,7 +256,6 @@ sub GenerateFiles
 		HAVE_GCC__SYNC_INT32_CAS                    => undef,
 		HAVE_GCC__SYNC_INT32_TAS                    => undef,
 		HAVE_GCC__SYNC_INT64_CAS                    => undef,
-		HAVE_GETHOSTBYNAME_R                        => undef,
 		HAVE_GETIFADDRS                             => undef,
 		HAVE_GETOPT                                 => undef,
 		HAVE_GETOPT_H                               => undef,