I use mads Whitespace bundle: https://github.com/mads379/Whitespace.tmbundle to flag trailing whitespace.

https://github.com/mads379/Whitespace.tmbundle/commit/ac6082c8f

I'd rather have the previous behavior which highlights all trailing whitespace.

https://github.com/mads379/Whitespace.tmbundle/blob/011dd0e/Syntaxes/Trailin...

Is there a way I could select which behavior was used in the Syntax file based on an environmental variable?

Syntaxes/Trailing Whitespace.tmLanguage https://github.com/mads379/Whitespace.tmbundle/blob/master/Syntaxes/Trailing...