[Scons-users] absolute/relative paths in CPPPATH

[ml]

Hi!

I have a SConstruct file e.g.:

/maindir/dir1/SConstruct

where I have env.Append(CPPPATH="/maindir/dir1") and it builds a program1 ... 
note the absolute path. When I run scons in that directory then the absolute 
path is converted to a relative one and it executes the compiler with "-I.". 
That is OK so far. Then I have a second SConstruct e.g.:

/maindir/dir2/SConstruct

which imports the first one and uses some of its objects and builds program2. 
The problem is that the CPPPATH in the first SConstruct is left as absolute path 
and it does not use the build cache because the compile command is different so 
it compiles the same targets (object files) again despite that it was already 
built with /maindir/dir1/SConstruct.

Is there any option to force CPPPATH to use always absolute path? I found 
SCons.Node.FS.RootDir which might behave this way but it is unreachable as e.g. 
env.Append(CPPPATH=RootDir("/maindir/dir1")).

Thanks
David