Selecting sources depending on target platform

From: emildotchevski (emildotchevski_at_[hidden])
Date: 2005-08-04 00:24:42

This is a question about using different cpp files in a given lib 
depending on the target platform.

I have the following directory structure:

/code/src/lib1/:
file_1.cpp
file_2.cpp

/code/sys/nt/lib1:
file_a.cpp
file_b.cpp

/code/sys/linux/lib1:
file_a.cpp
file_b.cpp

I would like for the jamfiles of libs under /code/src/... to glob 
for cpp files in their folder plus a folder under /code/sys 
depending on the target platform and the name of the lib.

For example, I want lib1 on nt to get these sources:

/code/src/lib1/*.cpp
/code/sys/nt/lib1/*.cpp

The same lib1 on linux should get these sources:

/code/src/lib1/*.cpp
/code/sys/linux/lib1/*.cpp

Ideally this would be set up globally for all libs under /code/src, 
so that when a new lib is added as /code/src/newlib, it utomatically 
knows to get everything in /code/src/newlib plus anything 
in /code/sys/PLATFORMID/newlib.

Since I am new to boost.build, please let me know if my set up could 
be improved somehow, or if a simple change in the directory 
structure would make it easier to get the behavior I need.

Thanks,
Emil