Current mvn3 (and possibly maven2) launcher doesn't respect the GENTOO_VM env. var. I'm attaching a patch for review. I'll commit if agreed although I can't figure out where this file comes from it's not identical to the one in ${FILESDIR}.
Created attachment 335566 [details, diff] Patch to fox the issue
Will need to do something like that or GENTOO_VM won't be respected indeed. Good catch. One thing that comes to mind looking at the is there probably should be a MAVEN_RESPECT_JAVA_HOME variable as there is for ant. The patch will make it otherwise hard to use user installed vms. The file itself can be found in the maven tarball, it's upstreams script.
