[gradle|jpms|eclipse|buildship] Add modularity support to Buildship

eclipse-modularity.gradle

// - Adds modularity support to Buildship

// Code is originally from https://github.com/java9-modularity/gradle-modules-plugin/issues/33#issue-376998502

apply plugin: 'eclipse'

eclipse {
	classpath {
		file {
			whenMerged {
				entries.findAll { isModule(it) }.each {
					it.entryAttributes['module'] = 'true'
				}

				entries.findAll { isSource(it) && isTestScope(it) }.each {
					it.entryAttributes['test'] = 'true'
				}

				entries.findAll { isLibrary(it) && isTestScope(it) }.each {
					it.entryAttributes['test'] = 'true'
				}
			}
		}
	}
}

def isLibrary(entry) { entry.properties.kind == 'lib' }
def isTestScope(entry) { entry.entryAttributes['gradle_used_by_scope'] == 'test' }
def isModule(entry) { isLibrary(entry) && !isTestScope(entry) }
def isSource(entry) { entry.properties.kind == 'src' }