[Scons-users] Mixing configuration and nodes

[Ludovic Courtès]

Hello,

I’m trying to achieve the following: My software project has a
dependency D; if D is present on the system then use it, otherwise
download it and build it.

In addition, I want to check whether an optional header of D is
available or not, using ‘CheckCXXHeader’.  This check must be performed
either on the system’s D, or on the just-downloaded D.

I implemented the download-and-build-D part using nodes, via
‘env.Command’.

However, my understanding is that configuration necessarily happens
_before_ nodes are considered.  Ideally, I would like to make the check
for D’s header happen _after_ the download-and-build-D nodes have
completed, but that does not seem to be feasible.

Any suggestions?

Thanks in advance,
Ludovic.