Update devel/gradle to 3.4. Fix the package to actually work.

Notable changes follow.

Gradle 3.4

- Compile Avoidance. We've introduced a new mechanism for up-to-date
  checking of Java compilation that is sensitive to public API changes
  only.
- A stable incremental Java compiler.
- brand new Java Library Plugin. Use this when building a component
  intended to be used as a dependency from another project.
- The JaCoCo plugin now allows you to enforce code coverage metrics and
  fail the build if they're not met.
- The default version of JaCoCo used by the JaCoCo plugin has been
  raised and the plugin is now Java 9-ready.
- The Checkstyle plugin now allows a maximum number of warnings or
  errors to be configured.

  https://docs.gradle.org/3.4/release-notes.html

Gradle 3.3

- This release of Gradle makes the gradle tasks report much faster for
  medium-to-large projects.
- It is now possible to compile native applications using Visual Studio
  2015.
- Kotlin build script support has further improved with significantly
  faster startup performance, increased API parity with Groovy-based
  build scripts, and better interoperability with Groovy plugins.
- Scala compilation startup time in large multi-project builds has been
  improved through enhancements to Gradle's integration with the Zinc
  Scala compiler.
- Tooling API generates more progress events.
- The Gradle GUI has been deprecated and will be removed in Gradle 4.0.

  https://docs.gradle.org/3.3/release-notes.html

Gradle 3.2.1

- GRADLE-3582: Gradle wrapper fails to escape arguments with nested
  quotes
- GRADLE-3583: Newlines in environment variables used by the wrapper
  breaks application plugin shell script

Gradle 3.2

- Incremental build support, which now has better up-to-date checking
  for Java compilation, copying, and archiving.
- The buildDependents task is now available in native builds as well via
  new assembleDependents and buildDependents tasks.
- Significantly improved import times.
- Improved support for multi-project builds with Kotlin.
- The shortcut syntax for declaring tasks (via <<) has now been
  deprecated.

  https://docs.gradle.org/3.2/release-notes.html

Gradle 3.1

- Composite Builds for multi-project builds where not all projects are
  in the same directory hierarchy.
- Incremental Build support.
- Faster dependency resolution.
- Build cancellation has improved when using the Daemon.

  https://docs.gradle.org/3.1/release-notes.html


(fhajny)