The problems with adding the code directly to the Wine config path are:
1) We package the tools along with the project - that way, if the tools are updated for a giving build, they will always be available with that build. I've done too much code archeology where I couldn't build a release because of subtle differences between tool versions, and I don't want to play that. 2) Our release procedure states that the developers are to make the code available to a software configuration control and management person, and they regenerate the project. The less configuration they have to do beforehand the better. 3) There can be multiple copies of the project checked out of CVS - I would like to be able to just do a "cvs co project; cd project; ./m" and have a build.
Adding the tools to Wine's path will work, however it introduces a point of difference between running under CMD.EXE under Windows and running under Wine in that one way you can dynamically extend the path, one way you cannot.