This re-covers the http://nodejs.org/api/addons.html case for which the "build" directory was added in 00686415, but doesn't break cross-environment projects that use the build directory for including concatenated/minified source. Mazel tov!

Now linking to the official npm FAQ entry (with tl;dr) rather than straight to mikeal's blog post

The "build" directory is lost in this refactor, as many JS projects
do wish to include a minified/concatenated version of their source
in the "build" folder in source control.

This is to exclude compiled code from nodejs addons.
Reference: http://nodejs.org/api/addons.html

according to the community since recent changes.

see: http://www.mikealrogers.com/posts/nodemodules-in-git.html
by @mikeal
(cherry picked from commit 44b47ec5bd0222ccf55efe5bcdb8bd3c55271803)