GROOVY-12040: restore @Builder retention to RUNTIME in 5.0.x

src/main/java/groovy/transform/builder/Builder.java

@@ -75,7 +75,7 @@
  * @see groovy.transform.builder.InitializerStrategy
  */
 @Documented
-@Retention(RetentionPolicy.SOURCE)
+@Retention(RetentionPolicy.RUNTIME)
 @Target({ ElementType.TYPE, ElementType.CONSTRUCTOR, ElementType.METHOD})
 @GroovyASTTransformationClass({
         "groovy.transform.builder.BuilderASTStubber",

src/test/groovy/org/codehaus/groovy/transform/BuilderTransformTest.groovy

@@ -839,4 +839,19 @@ final class BuilderTransformTest {
         assert new Captain(Captain.createInitializer().first('Kathryn').last('Janeway')).toString() == 'Kathryn Janeway'
         '''
     }
+
+    @Test // GROOVY-12040
+    void testBuilderAnnotationVisibleAtRuntime() {
+        assertScript shell, '''
+            @Builder(builderStrategy=SimpleStrategy, prefix='')
+            class ConnectionSettings {
+                String host = 'localhost'
+            }
+
+            Builder ann = ConnectionSettings.getAnnotation(Builder)
+            assert ann != null
+            assert ann.builderStrategy() == SimpleStrategy
+            assert ann.prefix() == ''
+        '''
+    }
 }