halide/Halide — pull request #370 by steven-johnson (2014-07-11 21:16:20+00:00)
Title: Add Explicit API for runtime settings (Issue #367, part 1)

Only read initial values for runtime settings from env vars once, then
cache them in a global structure; this allows for embedders to easily
control all settings, regardless of env var settings.

(Note that codegen settings will be done as a followup to this.)