All of these suggestions are there to shorten the <available>, <target unless>, <fail> combo necessary to achieve the same effect. I'd like to see us settle on one and only one approach. Perl's "there's is more than one way to do it" does not exactly fit into my picture of Ant.
Personally I'm not really decided between <require> and <fail unless>. The first one saves one takes the second one might be useful in a broader range of use cases where available does not apply. Stefan
