display an explicit warning when netlink headers are missing

"netlink headers not found" implicitely means we have to install the
kernel headers. Make this explicit.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

diff --git a/configure.ac b/configure.ac
index 9fbd914fd99b5b5d41375ea0415386c8c4253cb1..25b77ebb5f8602f825b62287e51f14199f378144 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -25,7 +25,7 @@ AS_AC_EXPAND(LOCALSTATEDIR, $localstatedir)
 AS_AC_EXPAND(LXCPATH, "${localstatedir}/lib/lxc")
 AS_AC_EXPAND(LXC_GENERATE_DATE, "$(date)")
 
-AC_CHECK_HEADERS([linux/netlink.h linux/genetlink.h], [], AC_MSG_ERROR([netlink headers not found]),
+AC_CHECK_HEADERS([linux/netlink.h linux/genetlink.h], [], AC_MSG_ERROR([netlink headers not found. Please install the linux kernel headers.]),
 [#include <linux/types.h>
 #include <bits/sockaddr.h>
 #include <linux/socket.h>])