files

Lots of information missing here; check out the old 4.x documentation for more details.

Some work has been done to make proper per-file configurations possible. It is now possible to specify any configuration value on a file or set of files.

filter "files:**.x"
  -- configuration for .x files

When using the old-style configuration() filter, you must use a positive filter match.

-- this will work
configuration { "**.lua or **.x or **.png" }

-- this will not; no "not" allowed
configuration { "not **.cpp" }

This rule is to prevent terms like "not Debug" from matching against file names when building file configurations.