Force resolution of _res for correct detection.
bz#2259, from sconeu at yahoo.com.
diff --git a/configure.ac b/configure.ac
index 02587e8..ec8f50d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3969,7 +3969,10 @@
#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])