Automated build updates

build.gradle

@@ -15,36 +15,45 @@ archivesBaseName = 'jSerialComm'
 version = '2.6.2'
 ext.moduleName = 'com.fazecast.jSerialComm'
 
+if (hasProperty('manualBuild'))
+{
+  assert hasProperty('java6Home'): "Set the property 'java6Home' in your gradle.properties file pointing to a Java 6 JDK installation"
+  assert hasProperty('java9Home'): "Set the property 'java9Home' in your gradle.properties file pointing to a Java 9 JDK installation"
+}
+
 sourceCompatibility = 1.6
 targetCompatibility = 1.6
 javadoc.options.links("https://docs.oracle.com/javase/9/docs/api/")
 javadoc.options.addBooleanOption('html4', true)
 
-def java6ExecutablesPath = new File(java6Home, 'bin')
-def java9ExecutablesPath = new File(java9Home, 'bin')
-def java6Executables = [:].withDefault { execName ->
-  def executable = new File(java6ExecutablesPath, execName)
-  executable
-}
-def java9Executables = [:].withDefault { execName ->
-  def executable = new File(java9ExecutablesPath, execName)
-  executable
-}
-
-tasks.withType(JavaCompile) {
-  options.with {
-    fork = true
-    forkOptions.javaHome = file(java6Home)
+if (hasProperty('manualBuild'))
+{
+  def java6ExecutablesPath = new File(java6Home, 'bin')
+  def java9ExecutablesPath = new File(java9Home, 'bin')
+  def java6Executables = [:].withDefault { execName ->
+    def executable = new File(java6ExecutablesPath, execName)
+    executable
+  }
+  def java9Executables = [:].withDefault { execName ->
+    def executable = new File(java9ExecutablesPath, execName)
+    executable
+  }
+  
+  tasks.withType(JavaCompile) {
+    options.with {
+      fork = true
+      forkOptions.javaHome = file(java6Home)
+    }
+  }
+  tasks.withType(Javadoc) {
+    executable = java9Executables.javadoc
+  }
+  tasks.withType(Test) {
+    executable = java6Executables.java
+  }
+  tasks.withType(JavaExec) {
+    executable = java6Executables.java
   }
-}
-tasks.withType(Javadoc) {
-  executable = java9Executables.javadoc
-}
-tasks.withType(Test) {
-  executable = java6Executables.java
-}
-tasks.withType(JavaExec) {
-  executable = java6Executables.java
 }
 
 sourceSets {