Follow Ralf Wildenhues' advice for avoiding dead-code elimination

  in configure test for in6addr_any.

bk: 4d92b74emekMvZ-rkY3DaBaqdJV6QQ

diff --git a/sntp/m4/ntp_ipv6.m4 b/sntp/m4/ntp_ipv6.m4
index b46ff8e7c2bcb107690cf839350680ce1ff96258..8ea9d6783a43ea0847e131783b59925c0b487bd6 100644 (file)
--- a/sntp/m4/ntp_ipv6.m4
+++ b/sntp/m4/ntp_ipv6.m4
@@ -345,27 +345,31 @@ esac
 
 AC_CACHE_CHECK(
     [for in6addr_any],
-    [isc_cv_have_in6addr_any],
-    [AC_LINK_IFELSE(
-       [AC_LANG_PROGRAM(
-           [[
-               #include <sys/types.h>
-               #include <sys/socket.h>
-               #include <netinet/in.h>
-               $isc_netinetin6_hack
-               $isc_netinet6in6_hack
-               
-               struct in6_addr * pin6addr_any = &in6addr_any;
-           ]],
-           [[
-           ]]
-       )],
-       [isc_cv_have_in6addr_any=yes],
-       [isc_cv_have_in6addr_any=no]
-    )]
+    [isc_cv_in6addr_any_links],
+    [
+       SAVED_LIBS="$LIBS"
+       LIBS="$LDADD_LIBNTP $LIBS"
+       AC_LINK_IFELSE(
+           [AC_LANG_PROGRAM(
+               AC_INCLUDES_DEFAULT [[
+                   #include <sys/socket.h>
+                   #include <netinet/in.h>
+                   $isc_netinetin6_hack
+                   $isc_netinet6in6_hack
+               ]],
+               [[
+                   printf("%x", in6addr_any.s6_addr[15]);
+               ]]
+           )],
+           [isc_cv_in6addr_any_links=yes],
+           [isc_cv_in6addr_any_links=no]
+       )
+       LIBS="$SAVED_LIBS"
+       AS_UNSET([SAVED_LIBS])
+    ]
 )
 
-case "$isc_cv_have_in6addr_any" in
+case "$isc_cv_in6addr_any_links" in
  no)
     AC_DEFINE([ISC_PLATFORM_NEEDIN6ADDRANY], [1], [missing in6addr_any?])
 esac