Force resolution of _res for correct detection.

bz#2259, from sconeu at yahoo.com.

diff --git a/configure.ac b/configure.ac
index 02587e8d7c1dabb5543b1f9fa3bae02c54f3afc6..ec8f50d2d5b7ee58392e75a0c992b3a737c41331 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -3969,7 +3969,10 @@ AC_LINK_IFELSE([AC_LANG_PROGRAM([[
 #include <arpa/nameser.h>
 #include <resolv.h>
 extern struct __res_state _res;
-               ]], [[ ]])],
+               ]], [[
+struct __res_state *volatile p = &_res;  /* force resolution of _res */
+return 0;
+               ]],)],
                [AC_MSG_RESULT([yes])
                 AC_DEFINE([HAVE__RES_EXTERN], [1],
                    [Define if you have struct __res_state _res as an extern])