diff --git a/contrib/platform/build.xml b/contrib/platform/build.xml
index 65fd1c1586..349e61985a 100644
--- a/contrib/platform/build.xml
+++ b/contrib/platform/build.xml
@@ -64,31 +64,31 @@
 
     -->
 
-    <target name="-do-jar-without-manifest">
-       <jar jarfile="${dist.jar}" compress="${jar.compress}">
-         <manifest>
-           <attribute name="Main-Class" value="com.sun.jna.Native"/>
-           <attribute name="Manifest-Version" value="1.0"/>
-           <attribute name="Implementation-Title" value="${impl.title}"/>
-           <attribute name="Implementation-Vendor" value="${vendor}"/>
-           <attribute name="Implementation-Version" value="${impl.version}"/>
-           <attribute name="Specification-Title" value="${spec.title}"/>
-           <attribute name="Specification-Vendor" value="${spec.vendor}"/>
-           <attribute name="Specification-Version" value="${spec.version}"/>
-           <!--
-              OSGi Bundle attributes
-              See http://www.osgi.org/Specifications/Reference
-            -->
-           <attribute name="Bundle-Category" value="jni"/>
-           <attribute name="Bundle-ManifestVersion" value="2"/>
-           <attribute name="Bundle-Name" value="jna-platform"/>
-           <attribute name="Bundle-Description" value="JNA Platform Library"/>
-           <attribute name="Bundle-SymbolicName" value="com.sun.jna.platform"/>
-           <attribute name="Bundle-Version" value="${osgi.version}"/>
-           <attribute name="Bundle-RequiredExecutionEnvironment" value="J2SE-1.4"/>
-           <attribute name="Bundle-Vendor" value="${vendor}"/>
-           <attribute name="Require-Bundle" value="com.sun.jna;bundle-version=&quot;${osgi.version}&quot;"/>
-           <attribute name="Export-Package"
+    <target name="-pre-jar">
+        <tempfile deleteonexit="true" destdir="${build.dir}" property="tmp.manifest.file"/>
+        <manifest file="${tmp.manifest.file}" mode="replace">
+            <attribute name="Main-Class" value="com.sun.jna.Native"/>
+            <attribute name="Manifest-Version" value="1.0"/>
+            <attribute name="Implementation-Title" value="${impl.title}"/>
+            <attribute name="Implementation-Vendor" value="${vendor}"/>
+            <attribute name="Implementation-Version" value="${impl.version}"/>
+            <attribute name="Specification-Title" value="${spec.title}"/>
+            <attribute name="Specification-Vendor" value="${spec.vendor}"/>
+            <attribute name="Specification-Version" value="${spec.version}"/>
+            <!--
+               OSGi Bundle attributes
+               See http://www.osgi.org/Specifications/Reference
+             -->
+            <attribute name="Bundle-Category" value="jni"/>
+            <attribute name="Bundle-ManifestVersion" value="2"/>
+            <attribute name="Bundle-Name" value="jna-platform"/>
+            <attribute name="Bundle-Description" value="JNA Platform Library"/>
+            <attribute name="Bundle-SymbolicName" value="com.sun.jna.platform"/>
+            <attribute name="Bundle-Version" value="${osgi.version}"/>
+            <attribute name="Bundle-RequiredExecutionEnvironment" value="J2SE-1.4"/>
+            <attribute name="Bundle-Vendor" value="${vendor}"/>
+            <attribute name="Require-Bundle" value="com.sun.jna;bundle-version=&quot;${osgi.version}&quot;"/>
+            <attribute name="Export-Package"
                    value="
 com.sun.jna.platform,
 com.sun.jna.platform.dnd,
@@ -100,9 +100,7 @@ com.sun.jna.platform.win32.COM.tlb,
 com.sun.jna.platform.win32.COM.tlb.imp,
 com.sun.jna.platform.wince
 "/>
-         </manifest>
-         <fileset dir="${build.classes.dir}"/>
-       </jar>
+        </manifest>
     </target>
 
     <target name="test" depends="init,compile,compile-test,-pre-test-run" description="Run platform unit tests.">