GT-3127: Gradle 5.6 support.

gradle/javaProject.gradle

@@ -161,3 +161,24 @@ ext.addExports = { List<String> exports ->
 		}
 	}
 }
+
+// Fixup generated Eclipse projects
+apply plugin: 'eclipse'
+eclipse.classpath.file.whenMerged { classpath ->
+
+	// Gradle 5.6 has a bug that creates duplicate classpath entries, so we must dedupe them.
+	// https://github.com/gradle/gradle/issues/10393 
+	classpath.entries.unique(true) {
+		(it instanceof org.gradle.plugins.ide.eclipse.model.ProjectDependency) ? it.path : it
+	}
+	
+	// Prevent Gradle 5.6 from setting the 'test' attribute on our test source folders and jars. 
+	// If we don't do this, things that we have outside of test directories that depend on test 
+	// libraries (like junit) will not compile in Eclipse.
+	classpath.entries.findAll {
+		it.kind == 'src' || it.kind == 'lib'
+	}.each { 
+		it.entryAttributes['test'] = 'false' 
+	}
+}
+