Scons in Scratchbox: Can't find g++ - environment-variables

Question

I've been using sbox with a Make-based codebase with no problems. Now
I'm using a scons-based codebase, and am getting some odd problems.
It seems that within scratchbox, scons can't find g++. For example, it
attempts to execute things like:
o hello hello.c
When it should be doing:
g++ -o hello hello.c
So presumably its g++ string variable is empty. g++ is present and in
the PATH - "which g++" produces /scratchbox/compilers/bin/g++.
The same source builds fine outside of scratchbox, so it shouldn't be
a problem with scons or the codebase. There are no special environment
variables set outside of scratchbox when it works.
If I symbolically link /usr/bin/g++ to /scratchbox/compilers/bin/g++,
it gets a bit further (produces the correct-looking g++ commands) but
then upon executing them produces:
sb_gcc_wrapper (g++):
/scratchbox/compilers/arm-linux-cs2007q3-51sb3/bin/sbox-arm-none-linux-gnueabi-g++:
No such file or directory
The file listed is present.
PATH contains /scratchbox/compilers/bin, SBOX_REDIRECT_FROM_DIRS contains /usr/bin and SBOX_REDIRECT_TO_DIRS contains /scratchbox/compilers/bin, so I think it should be able to find it.
Any suggestions would be appreciated!
Thanks,
Ray
Edit: Perhaps related - it also can't find pkg-config unless I prepend the full path within the scons file

Answer 1

scons does not propagate the PATH environment variable, so testing e.g. 'which g++' doesn't help much.
Either set the compilers directly, e.g.
env['CXX'] = '/scratchbox/compilers/bin/g++'
Build your own explicit PATH
path = ['/scratchbox/compilers/bin/','/bin', '/usr/bin', '/sbin','/usr/sbin']
env = Environment(ENV = {'PATH' : path})
Or use the PATH env variable from your shell
import os
env = Environment(ENV = {'PATH' : os.environ['PATH']})