[LTP] [PATCH 2/2] check for RES_USE_INET6 during configure

[Khem Raj <raj.khem@gmail.com>]

glibc 2.30 has remove RES_USE_INET6 define which has been on its way out
since 2.26 release, this check ensures that we detect it before using it

Signed-off-by: Khem Raj <raj.khem@gmail.com>
---
 configure.ac                                        | 13 +++++++++++++
 testcases/network/multicast/mc_gethost/mc_gethost.c |  6 ++++++
 2 files changed, 19 insertions(+)

diff --git a/configure.ac b/configure.ac
index 2255b5c181..ed7acccb01 100644
--- a/configure.ac
+++ b/configure.ac
@@ -91,6 +91,19 @@ AC_CHECK_FUNCS([ \
     vmsplice \
 ])
 
+#check defines
+AC_MSG_CHECKING([for RES_USE_INET6])
+AC_COMPILE_IFELSE( [AC_LANG_PROGRAM([[#include <resolv.h>]],
+  [[char dummy[RES_USE_INET6];]])],
+  [
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED([HAVE_RES_USE_INET6], 1, [Define to 1 if you have the RES_USE_INET6 macro.])
+  ],
+  [
+    AC_MSG_RESULT([no])
+    AC_DEFINE_UNQUOTED([HAVE_RES_USE_INET6], 0, [Define to 1 if you have the RES_USE_INET6 macro.])
+  ]
+)
 # Tools knobs
 
 # Expect
diff --git a/testcases/network/multicast/mc_gethost/mc_gethost.c b/testcases/network/multicast/mc_gethost/mc_gethost.c
index 9cc15d086b..d1cae5441a 100644
--- a/testcases/network/multicast/mc_gethost/mc_gethost.c
+++ b/testcases/network/multicast/mc_gethost/mc_gethost.c
@@ -17,6 +17,8 @@
 #include <string.h>
 #include <stdlib.h>
 
+#include "config.h"
+
 #ifndef LOG_PERROR
 #define LOG_PERROR 0
 #endif
@@ -50,8 +52,12 @@ usage:
 		argv++, argc--;
 	}
 	if (argc >= 1 && !strcmp(*argv, "-6")) {
+#if HAVE_RES_USE_INET6
 		af = AF_INET6, size = IN6ADDRSZ;
 		_res.options |= RES_USE_INET6;
+#else
+		af = AF_INET, size = INADDRSZ;
+#endif
 		argv++, argc--;
 	}
 	if (argc >= 1 && !strcmp(*argv, "-f")) {
-- 
2.22.0