Add debug output showing sconscript being processed?

[mwichmann]

Filed to capture a thread here:

https://stackoverflow.com/questions/76520575/scons-overriding-sconscript-function-to-get-a-list-all-loaded-sconscripts

Should one wish to see the scripts being processed, there's not a particularly clean way to set this up, due to the way things get evaluated: hooking the SConscript function via a decorator ends up with references to things unavailable at the time. It would, however, be easy for SCons itself to provide this information, perhaps enabled by a debug flag. That is, it could optionally go from

scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: done reading SConscript files.
scons: Building targets ...
...
scons: done building targets.

to

scons: Reading SConscript files ...
Reading src/SConscript
Reading src/lib/network/SConscript
...
scons: done reading SConscript files.
...

[mwichmann]

Grrr, closed in error - wrong browser tab. Going to remove the previous close comment so github doesn't link this to a PR it has no relation to.