diff -Naur a/build-clean.xml b/build-clean.xml
--- a/build-clean.xml	2016-10-10 18:26:04.056935377 +0200
+++ b/build-clean.xml	2016-10-10 18:47:11.662036536 +0200
@@ -59,18 +59,8 @@
 	<assertions><enable/></assertions>
 
 	<!-- set version string based on git-describe -->
-	<exec executable="git" failifexecutionfails="false"
-		errorProperty="git.errror" outputproperty="git.describe" resultproperty="git.result">
-		<arg value="describe" />
-		<arg value="--always" />
-		<arg value="--abbrev=4" />
-		<arg value="--dirty" />
-	</exec>
-	<condition property="git.revision" value="${git.describe}" else="@unknown@">
-		<and>
-			<equals arg1="${git.result}" arg2="0" />
-			<isset property="git.describe" />
-		</and>
+	<condition property="git.revision" value="@unknown@" else="@unknown@">
+		<isset property="git.describe" />
 	</condition>
 
 	<!-- =================================================================== -->