Sort: reduced stack depth to lg(n) in quickSort
Sort: reduced stack depth to lg(n) in quickSort

Doing the tail recursion elimination explicitly
seems safer than leaving it to the compiler;
the code is still clean and easy to understand.

R=r, r2, gri
CC=golang-dev
http://codereview.appspot.com/3373041

Committer: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>

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