Try fixing mx.cmd

Signed-off-by: Stefan Marr <[email protected]>

build.xml

@@ -25,8 +25,8 @@
       <os family="windows"/>
     </condition>
 
-    <property name="mx.cmd" value="../../mx/mx" />
-    <property name="mx.cmd" value="..\..\mx\mx.cmd" if:true="${is.windows}" />
+    <property name="mx.cmd" location="${lib.dir}/mx/mx" unless:true="${is.windows}" />
+    <property name="mx.cmd" location="${lib.dir}\mx\mx.cmd" if:true="${is.windows}" />
 
     <property name="build.dir"   value="build"/>
     <property name="classes.dir" value="${build.dir}/classes"/>
@@ -69,7 +69,7 @@
         <matches string="${java.version}" pattern="^9\."/>
       </condition>
     </target>
-    
+
     <target name="check-truffle-available">
         <available file="${lib.dir}/truffle/.git" property="truffle.present"/>
     </target>
@@ -93,7 +93,7 @@
           http://www.oracle.com/technetwork/oracle-labs/program-languages/downloads/index.html
           for a JVMCI JDK Download.
       </echo>
-      
+
       <exec executable="${mx.cmd}" dir="${graal.dir}" failonerror="true">
         <arg value="build" />
       </exec>
@@ -307,7 +307,7 @@
     <target name="superinstructions-tests" depends="compile-som">
       <exec executable="tests/superinstructions/test.sh" failonerror="true"></exec>
     </target>
-    
+
     <target name="update-test-data" depends="compile-som" description="Updates the test data for DynamicMetrics and SuperInstructions">
       <exec executable="tests/dym/test.sh" failonerror="true">
         <arg value="update" />