From 4c18acffd73f874cbf5ba0d0367bbcaeb99328ac Mon Sep 17 00:00:00 2001
From: Eric Blake <eblake@redhat.com>
Date: Thu, 19 Jan 2012 13:35:39 -0700
Subject: [PATCH] build: skip lxc with too-old glibc

Since we already require the kernel to be new enough to support
LO_FLAGS_AUTOCLEAR, we might as well also require glibc to be
new enough to support epoll_create1().

* configure.ac (with_lxc): We require glibc 2.9 for LXC.
Reported and tested by Philipp Hahn.
---
 configure.ac | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index 729ba9b29..6709ebf18 100644
--- a/configure.ac
+++ b/configure.ac
@@ -734,16 +734,17 @@ if test "$with_lxc" = "yes" || test "$with_lxc" = "check"; then
     AC_TRY_LINK([
         #include <sched.h>
         #include <linux/loop.h>
+        #include <sys/epoll.h>
     ], [
-        unshare (!LO_FLAGS_AUTOCLEAR);
+        unshare (!(LO_FLAGS_AUTOCLEAR + EPOLL_CLOEXEC));
     ], [
         with_lxc=yes
     ], [
         if test "$with_lxc" = "check"; then
             with_lxc=no
-            AC_MSG_NOTICE([Function unshare() not present in <sched.h> header but required for LXC driver, disabling it])
+            AC_MSG_NOTICE([Required kernel features were not found, disabling LXC])
         else
-            AC_MSG_ERROR([Function unshare() not present in <sched.h> header, but required for LXC driver])
+            AC_MSG_ERROR([Required kernel features for LXC were not found])
         fi
     ])
 fi
-- 
2.39.5