[build] Simplified management of Groovy jar WRT grails/groovy joint b…

…uild.

There is one functional change here in that the build will now always use the groovy compiler from the version of groovy that we are compiling against. Previously, the joint build would always use the Groovy 1.8.2 compiler though I think this was unintended and just misconfiguration.

build.gradle

@@ -57,16 +57,19 @@ homeSrcDir = file("src")
 // configurations, so place the dependency in a shared variable. The
 // 'compile' is required so that Groovy appears as a dependency in the
 // artifacts' POMs.
-if(System.getProperty('groovy.jar')) {
-    groovyDependency = files(System.getProperty('groovy.jar'))
-    if(!groovyDependency?.singleFile?.exists()) {
-        def msg = "The groovy.jar system property points to ${System.getProperty('groovy.jar')} which does not exist."
-        throw new GradleException(msg)
+jointBuildGroovyJarProperty = System.getProperty('groovy.jar')
+if (jointBuildGroovyJarProperty) {
+    jointBuildGroovyJar = file(jointBuildGroovyJarProperty)
+    if (jointBuildGroovyJar.exists()) {
+        groovyDependency = dependencies.create(files(jointBuildGroovyJar))
+    } else {
+        throw new GradleException("The groovy.jar system property points to ${jointBuildGroovyJar.absolutePath} which does not exist.")
     }
-    gradleGroovyDependency = "org.codehaus.groovy:groovy-all:${gradleGroovyVersion}"
 } else {
-    groovyDependency = "org.codehaus.groovy:groovy-all:${groovyVersion}"
-    gradleGroovyDependency = "org.codehaus.groovy:groovy-all:${gradleGroovyVersion}"
+    groovyDependency = dependencies.create("org.codehaus.groovy:groovy-all:${groovyVersion}") {
+        exclude module:"commons-cli"
+        exclude module:"ant"
+    }
 }
 
 // Prevent multiple repositories being used, commented out as currently doesn't work.
@@ -143,18 +146,7 @@ subprojects { project ->
     }
 
     dependencies {
-        // Groovy
-        if(System.getProperty('groovy.jar')) {
-            // use the jar specified in the system property (the joint build specifies its own groovy jar)...
-            groovy gradleGroovyDependency
-        } else {
-            // resolve the dependency from a repo...
-            groovy( gradleGroovyDependency ) {
-                exclude module:"commons-cli"
-                exclude module:"ant"
-            }
-        }
-        compile groovyDependency
+        groovy groovyDependency
 
         if (project.name != "grails-docs") {
             // Logging