configure.ac: Fix test for libresolv on Mac OS 10.4.x.
The resolv.h header file won't compile without netinet/in.h being
included first.
diff --git a/configure.ac b/configure.ac
index 784107e..8d45409 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1011,7 +1011,10 @@
then
ac_save_LIBS="$LIBS"
LIBS="$LIBS -lresolv"
- AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <resolv.h>]],[[res_init();]])],
+ AC_LINK_IFELSE([AC_LANG_PROGRAM([[#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+#include <resolv.h>]],[[res_init();]])],
[AC_DEFINE(HAVE_RESOLV, 1, [Define if you have the resolver library and header])
RESOLVLIBS="-lresolv"])
LIBS="$ac_save_LIBS"