I tried to build slf4j 1.6.1 from source and the build failed with the following error:

org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.2:run (ant-osgi-test) on project integration: An Ant BuildException has occured: The following error occurred while executing this line:
java.io.FileNotFoundException: C:\Users\dick.jones.KINETX\Downloads\slf4j-1.6.1\integration\osgi-build.xml (The system cannot find the file specified)

I emailed Ceki Gulcu who said the file, osgi-build.xml, was inadvertently ommitted and asked that I enter this as a bug.