Enable native access in executable JARs

Support use from JDK 25 by adding Enable-Native-Access=ALL-UNNAMED to JARs that have a main class. Partially addresses compatibility with Java 25.

Author: wfouche

build.gradle

@@ -650,7 +650,8 @@ jar {
         attributes ([
             'Main-Class': 'org.python.util.jython',
             'Built-By': 'build.gradle',
-            'Automatic-Module-Name': 'org.python.jython2'
+            'Automatic-Module-Name': 'org.python.jython2',
+            'Enable-Native-Access': 'ALL-UNNAMED'
         ])
 
         attributes( [ // Build-Info section

build.xml

@@ -924,6 +924,7 @@ The text for an official release would continue like ...
                 <attribute name="Implementation-Vendor" value="Python Software Foundation"/>
                 <attribute name="Implementation-Title" value="Jython fat jar"/>
                 <attribute name="Implementation-Version" value="${jython.version}"/>
+                <attribute name="Enable-Native-Access" value="ALL-UNNAMED"/>
                 <!-- info section. ATTN: no blanks, no '.' in the names -->
                 <section name="Build-Info">
                     <attribute name="version" value="${jython.version}" />
@@ -948,6 +949,7 @@ The text for an official release would continue like ...
                 <attribute name="Implementation-Vendor" value="Python Software Foundation"/>
                 <attribute name="Implementation-Title" value="Jython fat jar with stdlib"/>
                 <attribute name="Implementation-Version" value="${jython.version}"/>
+                <attribute name="Enable-Native-Access" value="ALL-UNNAMED"/>
                 <!-- info section. ATTN: no blanks, no '.' in the names -->
                 <section name="Build-Info">
                     <attribute name="version" value="${jython.version}" />