From 65e97a66e62e6320a28c42f2d02219b1f84b717a Mon Sep 17 00:00:00 2001
From: Jan Engelhardt <jengelh@medozas.de>
Date: Thu, 13 Jan 2011 20:23:15 +0100
Subject: [PATCH] build: restore functionality of configure's --without-kbuild
 option

---
 configure.ac      | 60 ++++++++++++++++++++++++-----------------------
 doc/changelog.txt |  1 +
 2 files changed, 32 insertions(+), 29 deletions(-)

diff --git a/configure.ac b/configure.ac
index 509c104..871eecb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -49,35 +49,37 @@ if grep -q "CentOS release 5\." /etc/redhat-release 2>/dev/null ||
 	# Well, just a warning. Maybe the admin updated the kernel.
 	echo "WARNING: This distribution's shipped kernel is not supported.";
 fi;
-AC_MSG_CHECKING([kernel version that we will build against])
-krel="$(make -sC "$kbuilddir" M=. kernelrelease)";
-kmajor="${krel%%[[^0-9]]*}";
-kmajor="$(($kmajor+0))";
-krel="${krel:${#kmajor}}";
-krel="${krel#.}";
-kminor="${krel%%[[^0-9]]*}";
-kminor="$(($kminor+0))";
-krel="${krel:${#kminor}}";
-krel="${krel#.}";
-kmicro="${krel%%[[^0-9]]*}";
-kmicro="$(($kmicro+0))";
-krel="${krel:${#kmicro}}";
-krel="${krel#.}";
-kstable="${krel%%[[^0-9]]*}";
-kstable="$(($kstable+0))";
-if test -z "$kmajor" -o -z "$kminor" -o -z "$kmicro"; then
-	echo "WARNING: Version detection did not succeed. Continue at own luck.";
-else
-	echo "$kmajor.$kminor.$kmicro.$kstable in $kbuilddir";
-	if test "$kmajor" -gt 2 -o "$kminor" -gt 6 -o "$kmicro" -gt 37; then
-		echo "WARNING: You are trying a newer kernel. Results may vary. :-)";
-	elif test \( "$kmajor" -lt 2 -o \
-	    \( "$kmajor" -eq 2 -a "$kminor" -lt 6 \) -o \
-	    \( "$kmajor" -eq 2 -a "$kminor" -eq 0 -a "$kmicro" -lt 17 \) -o \
-	    \( "$kmajor" -eq 2 -a "$kminor" -eq 6 -a "$kmicro" -eq 18 -a \
-	    "$kstable" -lt 5 \) \); then
-		echo "ERROR: That kernel version is not supported. Please see INSTALL for minimum configuration.";
-		exit 1;
+if test -n "$kbuilddir"; then
+	AC_MSG_CHECKING([kernel version that we will build against])
+	krel="$(make -sC "$kbuilddir" M=. kernelrelease)";
+	kmajor="${krel%%[[^0-9]]*}";
+	kmajor="$(($kmajor+0))";
+	krel="${krel:${#kmajor}}";
+	krel="${krel#.}";
+	kminor="${krel%%[[^0-9]]*}";
+	kminor="$(($kminor+0))";
+	krel="${krel:${#kminor}}";
+	krel="${krel#.}";
+	kmicro="${krel%%[[^0-9]]*}";
+	kmicro="$(($kmicro+0))";
+	krel="${krel:${#kmicro}}";
+	krel="${krel#.}";
+	kstable="${krel%%[[^0-9]]*}";
+	kstable="$(($kstable+0))";
+	if test -z "$kmajor" -o -z "$kminor" -o -z "$kmicro"; then
+		echo "WARNING: Version detection did not succeed. Continue at own luck.";
+	else
+		echo "$kmajor.$kminor.$kmicro.$kstable in $kbuilddir";
+		if test "$kmajor" -gt 2 -o "$kminor" -gt 6 -o "$kmicro" -gt 37; then
+			echo "WARNING: You are trying a newer kernel. Results may vary. :-)";
+		elif test \( "$kmajor" -lt 2 -o \
+		    \( "$kmajor" -eq 2 -a "$kminor" -lt 6 \) -o \
+		    \( "$kmajor" -eq 2 -a "$kminor" -eq 0 -a "$kmicro" -lt 17 \) -o \
+		    \( "$kmajor" -eq 2 -a "$kminor" -eq 6 -a "$kmicro" -eq 18 -a \
+		    "$kstable" -lt 5 \) \); then
+			echo "ERROR: That kernel version is not supported. Please see INSTALL for minimum configuration.";
+			exit 1;
+		fi;
 	fi;
 fi;
 
diff --git a/doc/changelog.txt b/doc/changelog.txt
index 8c8018f..0286650 100644
--- a/doc/changelog.txt
+++ b/doc/changelog.txt
@@ -2,6 +2,7 @@
 HEAD
 ====
 Fixes:
+- build: restore functionality of `configure --without-kbuild`
 - xt_LOGMARK: fix detection of untracked connection for Linux >= 2.6.36