[cmake-developers] Introduce 'Unix Ninja' generator

[Brad King]

On 01/20/2015 10:42 AM, Daniel Levin wrote:
> - you need to explicitly load environment variables each time before build

This is the standard approach expected by Makefile and Ninja generators.
Even for builds with MSVC's cl tool we expect users to launch a command
prompt with the proper PATH, INCLUDE, LIB, etc. environment variables set,
and then run the build from there.

-Brad