Build: Add .settings for buildSrc on gradle eclipse

We have eclipse settings added to all projects when running gradle
eclipse, but buildSrc is its own special project that is not
encapsulated by allprojects blocks. This adds eclipse settings to
buildSrc.

buildSrc/build.gradle

@@ -80,3 +80,13 @@ eclipse {
     defaultOutputDir = new File(file('build'), 'eclipse')
   }
 }
+
+task copyEclipseSettings(type: Copy) {
+  from project.file('src/main/resources/eclipse.settings')
+  into '.settings'
+}
+// otherwise .settings is not nuked entirely
+tasks.cleanEclipse {
+  delete '.settings'
+}
+tasks.eclipse.dependsOn(cleanEclipse, copyEclipseSettings)