I tried a few different ways to run the build script with the modules I wanted to include ("zepto event ajax form touch"), and every time zepto.js was created, but zepto.min.js wasn't. Uglify threw an error.
I installed Uglify globally, ran in on zepto.js and got the following error:
$ uglifyjs zepto.js -o zepto.min.js
Parse error at zepto.js:867,8
Unexpected token: name (Fuchs)
Turns out "Thomas Fuchs" was sitting in the middle of zepto.js (not in a comment or quoted) and confusing the parser. It was just after these lines:
window.Zepto = Zepto
window.$ === undefined && (window.$ = Zepto)
Removing the "Thomas Fuchs" line solved the problem.
"Thomas Fuchs" are not valid keywords in JS (yet)
Thanks for letting us know. It was a whitespace snafu.