diff --git a/autogen.sh b/autogen.sh
index 07ceaccb..909caee3 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -26,42 +26,8 @@ fi
 echo "Creating help files..."
 perl syntax.pl
 
-# create changelog
-# the TZ hack is needed.
-# otherwise the log will have local timezone
-if test -z "$SVN"; then
-	SVN=svn
-fi
-if $SVN --version >/dev/null 2>/dev/null; then
-	if test -f $srcdir/ChangeLog; then
-		CHANGELOG_VERSION=`head -n 2 $srcdir/ChangeLog| grep '^r' | sed 's/^r\([0-9]*\).*/\1/'`
-	fi
-	if test -z "$CHANGELOG_VERSION"; then
-		echo "Getting ChangeLog from svn..."
-		TZ=UTC $SVN log -v > $srcdir/ChangeLog
-	else
-		SVN_VERSION=`LC_ALL=C $SVN info $srcdir | grep 'Last Changed Rev' | awk '{print $4}'`
-		if test -z "$SVN_VERSION"; then
-			echo "**Warning**: Couldn't get svn revision number. This is probably not an svn checkout."
-		else
-			if test $SVN_VERSION -eq $CHANGELOG_VERSION; then
-				echo ChangeLog is already up-to-date.
-			else
-				echo "Updating ChangeLog from version $CHANGELOG_VERSION to $SVN_VERSION..."
-				mv $srcdir/ChangeLog $srcdir/ChangeLog.prev
-				TZ=UTC $SVN log -v --incremental $srcdir -r $SVN_VERSION:`expr $CHANGELOG_VERSION + 1` > $srcdir/ChangeLog
-				cat $srcdir/ChangeLog.prev >> $srcdir/ChangeLog
-			fi
-		fi
-	fi
-else
-	if test -f $srcdir/ChangeLog; then
-		echo "**Warning**: svn not found, skipping ChangeLog updating. The reported irssi version may be incorrect."
-	else
-		echo "**Error**: svn not found, and ChangeLog file missing, can not determine version."
-		exit 1
-	fi
-fi
+$srcdir/update-changelog.sh
+test -f $srcdir/ChangeLog || exit 1
 
 files=`echo docs/help/in/*.in|sed -e 's,docs/help/in/Makefile.in ,,' -e 's,docs/help/in/,!,g' -e 's/\.in /.in ?/g'`
 cat docs/help/in/Makefile.am.gen|sed "s/@HELPFILES@/$files/g"|sed 's/?/\\?/g'|tr '!?' '\t\n' > docs/help/in/Makefile.am
diff --git a/update-changelog.sh b/update-changelog.sh
new file mode 100755
index 00000000..fe055b88
--- /dev/null
+++ b/update-changelog.sh
@@ -0,0 +1,15 @@
+#! /bin/sh
+
+srcdir=$1
+test -d $srcdir/.svn || exit
+SVN_VERSION=`LC_ALL=C svn info $srcdir 2>/dev/null | awk '/^Last Changed Rev/{print $4}'`
+test -n "$SVN_VERSION" || exit
+if test -f $srcdir/ChangeLog; then
+	CHANGELOG_VERSION=`awk 'NR == 2{print substr($1, 2);exit}' $srcdir/ChangeLog`
+fi
+if test -z "$CHANGELOG_VERSION"; then
+	TZ=UTC svn log -v $srcdir > $srcdir/ChangeLog
+elif test $SVN_VERSION -ne $CHANGELOG_VERSION; then
+	TZ=UTC svn log -v --incremental -r $SVN_VERSION:`expr $CHANGELOG_VERSION + 1` $srcdir | \
+	cat - $srcdir/ChangeLog > ChangeLog.$$ && mv ChangeLog.$$ $srcdir/ChangeLog
+fi