[Scons-dev] tracking command line argument changes in a custom tool ?

[Ram Bhamidipaty]

How do I track build variable changes in a tool ?

In my case I have a tool that I invoke like this:

env.MyTool("file.o" ["file.c"], V1=1, V2=2, ...)

The tool is a bit complicated - I use Builder() objects to construct a  
file that contains the command line arguments for the compiler and  
then I use another Builder() to run the compiler. This is modeled on  
the tools for fools wiki page.

The problem I am seeing is that if I change the variables used to  
invoke MyTool() scons does not rebuild the file.

Question: In a tool - how does one track variable changes that would  
require the output file to be regenerated?

Thanks for any help.