[PATCH v2 2/3] Introduce compat.h file to deal with old Linux api and fix build failure due to missing NETLINK_EXT_ACK

[Giulio Benetti <giulio.benetti@benettiengineering.com>]

In "compat.h" check if NETLINK_EXT_ACK exists, otherwise define it to fix
build failure and where at the moment <linux/netlink.h> is included
let's include "compat.h"

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
---
V1->V2:
* include "compat.h" in place of <linux/netlink.h>
---
 support/export/cache.c       |  2 +-
 support/export/cache_flush.c |  2 ++
 support/include/compat.h     | 10 ++++++++++
 utils/nfsdctl/nfsdctl.c      |  1 +
 4 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 support/include/compat.h

diff --git a/support/export/cache.c b/support/export/cache.c
index 2f128d7d..65008f51 100644
--- a/support/export/cache.c
+++ b/support/export/cache.c
@@ -40,7 +40,7 @@
 #include <netlink/genl/ctrl.h>
 #include <netlink/msg.h>
 #include <netlink/attr.h>
-#include <linux/netlink.h>
+#include "compat.h"
 
 #ifdef USE_SYSTEM_NFSD_NETLINK_H
 #include <linux/nfsd_netlink.h>
diff --git a/support/export/cache_flush.c b/support/export/cache_flush.c
index ed7b964f..2a24dec7 100644
--- a/support/export/cache_flush.c
+++ b/support/export/cache_flush.c
@@ -38,6 +38,8 @@ extern int no_netlink;
 #include "sunrpc_netlink.h"
 #endif
 
+#include "compat.h"
+
 static int nl_send_flush(struct nl_sock *sock, int family, int cmd)
 {
 	struct nl_msg *msg;
diff --git a/support/include/compat.h b/support/include/compat.h
new file mode 100644
index 00000000..83229b65
--- /dev/null
+++ b/support/include/compat.h
@@ -0,0 +1,10 @@
+#ifndef COMPAT_H
+#define COMPAT_H
+
+#include <linux/netlink.h>
+
+#ifndef NETLINK_EXT_ACK
+#define NETLINK_EXT_ACK 11
+#endif
+
+#endif /* COMPAT_H */
diff --git a/utils/nfsdctl/nfsdctl.c b/utils/nfsdctl/nfsdctl.c
index 016dd2eb..c7126748 100644
--- a/utils/nfsdctl/nfsdctl.c
+++ b/utils/nfsdctl/nfsdctl.c
@@ -26,6 +26,7 @@
 #include <netlink/msg.h>
 #include <netlink/attr.h>
 #include <linux/netlink.h>
+#include "compat.h"
 
 #include <readline/readline.h>
 #include <readline/history.h>
-- 
2.47.3