Add distMacApp task to Gradle build script

I'm not a MAC user so I'd to do it blind !
but now it's migrated from Ant an can be fine tuned.

README.md

@@ -187,7 +187,7 @@ Compiling YaCy:
 - Compile: `gradlew build` - then you can `./startYACY.sh` or `./startYACY.bat`.
 - Create a release tarball and zip archive: `gradlew packageDist`.
 - Create a Windows installer release exe: `gradlew distWinInstaller`.
-- Create a macOS release: not yet availabe with gradle (old build `ant distMacApp` (only works on macOS)).
+- Create a macOS release: `gradlew distMacApp`.
 - Work with Eclipse or other IDE: Within the IDE you also need to start the gradle build process
   because the servlet pages are not compiled by the IDE build process.
   after the dist procedure, the release can be found in the build/distributions subdirectory.

build.gradle

@@ -218,7 +218,7 @@ task copyFilesToDistDir (type: Copy, dependsOn : ['compileJava', 'jar', 'compile
     include 'gradle/**'
     include 'htroot/**'
     include 'langdetect/**'
-    include 'lib/**'
+    //include 'lib/**'  // do not copy old ant lib, gradle dependencies will be copied into lib by task copy copyDependenciesForDistribution
     include 'libbuild/**'
     include 'locales/**'
     include 'skins/**'
@@ -265,8 +265,6 @@ distributions {
             from 'build/RELEASE/MAIN'
             exclude 'lib/*.jar'
             // define unix/linux file permission
-            fileMode 0644
-            dirMode 0755
             eachFile { file ->
                 if(file.getName().endsWith(".sh")) {
                     file.setMode(0755)
@@ -440,3 +438,38 @@ gradle.startParameter.taskNames.each {
     expandedTaskList << (buildAliases[it] ? buildAliases[it] : it)
 }
 gradle.startParameter.taskNames = expandedTaskList.flatten()
+
+// create a Mac distribution archive
+import org.apache.tools.ant.taskdefs.condition.Os
+task distMacApp (type: Copy, dependsOn: ['copyFilesToDistDir'], group: 'distribution') {
+    description 'Bundles the project as a Mac distribution - task must run on Mac'
+ 
+    from 'build/RELEASE/MAIN'
+    into 'build/RELEASE/MAC/YaCy.app/Contents/MacOS'
+    eachFile { file ->
+        if(file.getName().endsWith(".sh")) {
+            file.setMode(0755)
+        }
+    }
+    copy {
+        from 'addon/YaCy.app'
+        into 'build/RELEASE/MAC/YaCy.app'
+    }
+    doLast {   
+        if (Os.isFamily(Os.FAMILY_MAC))  {
+            String Dst = project.ext.filterTokens.get('REPL_DATE')
+            String rNr = project.ext.filterTokens.get('REPL_REVISION_NR')
+            String branch = project.ext.filterTokens.get('branch')    
+            String theArchiveName = 'yacy' + branch + '_v' + project.version + '_' + Dst + '_' + rNr + '.dmg'
+
+            ant {
+                exec (executable:'hdiutil') {
+                    arg (line:'create -srcfolder build/RELEASE/MAC/YaCy.app build/distributions/' + theArchiveName)
+                }
+            }
+        } else {
+            println "this task [distMacApp] can only run on a Mac"
+        }
+    }
+}
+