Goal

• As a RHEL user I want to run RHEL Ant with arbitrary Java runtime I
  provide. I don't want any packaged Java to be installed with Ant
  because it wont't be used and it takes too much space/time to install
  it. I will take responsibility for supplying a suitable Java runtime
  to run Ant with. I acknowledge that this configuration is not
  supported by RHEL.

• As a user of Java container image based on RHEL UBI (eg. Eclipse
  Temurin UBI image) I want to be able to install RHEL Ant without
  pulling-in RHEL OpenJDK, as it takes considerable space and time.

• As a developer of a RHEL layered product (eg. OpenShift S2I) I want to
  be able to build a container image based on RHEL with RHEL Ant and
  Java runtime of my choice, either RHEL OpenJDK or arbitrary Java
  runtime I supply, not necessairly packaged as RPM package. In the
  second case, RHEL OpenJDK should not be included in the container
  image.

Acceptance Criteria

• It is possible to install ant-unbound without pulling in any packaged Java
• ant-unbound works after either setting JAVA_HOME to point to Java installation home, or setting PATH to contain java command, with JAVA_HOME having priority over PATH
• Basic usage of ant-unbound works with at least one Temurin version
• Basic usage of ant-unbound works with custom jlink-based Java installation