martine/ninja — pull request #623 by nico (2013-07-19 00:54:19+00:00)
Title: Fix diagnostic formatting regression caused by adaa91a33eb2cf23b88.

Ninja regressed to include a location for every file on the include stack for
nested diagnostics, i.e. it would print:

input:1: include.ninja:1: expected path

Fix this so that it prints only the current file location, like it used to:

include.ninja:1: expected path

Also add a test for this.