[Scons-users] pointer to info on using a project-built tool?

[Mats Wichmann]

A tool built using project sources needs to be used to generate binary
data files from text (json) input files.  We're having some weird
problems getting this to work (scons code that we thought would set the
absolute location of the tool seems to be getting replaced so there are
errors  claiming the tool is not found in the source directory of a file
being converted, where it of course is not).

The developer appears to have followed the instructions here, using a
generator.

http://www.scons.org/doc/latest/HTML/scons-user.html#chap-builders-writing

the complications are that the tool is built as part of the project
source, so it needs somehow to have built before the targets using it
are encountered (I think this is the reason a generator was used); and
the project supports several cross-building scenarios (meaning the tool
has to be built native, not for the target, so it can be run by the
build host)

Anybody know of a resource with guidance on such?  I haven't had luck
finding something applicable, maybe my google/stackoverflow-foo is too weak.