commit e84391ce665cef046967f796dd91026851d6bbf3
Author: Peter Volkov <pva@gentoo.org>
Date:   Mon Jun 20 10:50:29 2011 +0400

    build: use absolute path for M=
    
    Use absolute path for M during checking kernelrelease. This will force
    temporary objects be built in the current directory and not $kbuilddir
    as it happened, e.g. in the current kernel scripts/Kbuild.include
    try-run target (it is called with TMPOUT=M=. and during call
    pwd=$kbuilddir). This should fix sandbox violation in Gentoo:
    https://bugs.gentoo.org/show_bug.cgi?id=371997

diff --git a/configure.ac b/configure.ac
index 0660eea..14dae83 100644
--- a/configure.ac
+++ b/configure.ac
@@ -42,7 +42,7 @@ regular_CFLAGS="-Wall -Waggregate-return -Wmissing-declarations \
 
 if test -n "$kbuilddir"; then
 	AC_MSG_CHECKING([kernel version that we will build against])
-	krel="$(make -sC "$kbuilddir" M=. kernelrelease)";
+	krel="$(make -sC "$kbuilddir" M=$PWD kernelrelease)";
 	kmajor="${krel%%[[^0-9]]*}";
 	kmajor="$(($kmajor+0))";
 	krel="${krel:${#kmajor}}";