as we talked about it at #gentoo-java, you wrote that this check should be removed as libXt is not needed. filing this just as an reminder.
What's the status here? The ebuild says it's needed for headers.
As the ebuild says, checking through the sources, I find it still uses Xt headers so it's there as a build, but not runtime, dependency.
It may be possible to remove the header dependency (my digging showed them being included but not necessarily used), but we'd need to look at that in more detail.
Filed a bug to track that: http://icedtea.classpath.org/bugzilla/show_bug.cgi?id=2928