Force resolution of _res for correct detection.

bz#2259, from sconeu at yahoo.com.

1 files changed, 4 insertions, 1 deletions

diff --git a/configure.ac b/configure.ac
index 02587e8d7..ec8f50d2d 100644
--- 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])