+ <plugin>
+ <groupId>org.codehaus.mojo</groupId>
+ <artifactId>build-helper-maven-plugin</artifactId>
+ <version>1.8</version>
+ <executions>
+ <execution>
+ <id>add-source</id>
+ <phase>generate-sources</phase>
+ <goals>
+ <goal>add-source</goal>
+ </goals>
+ <configuration>
+ <sources>
+ <source>${project.build.directory}/generated-sources/config</source>
+ <source>${project.build.directory}/generated-sources/sal</source>
+ <source>src/main/xtend-gen</source>
+ </sources>
+ </configuration>
+ </execution>
+ </executions>
+ </plugin>