scons: Make the sim_objects parameter of SimObject mandantory.

If there really are no c++ sim_objects in the file, then sim_objects can
be set to [] which it used to default to.

This way, if someone hasn't remembered to update their SConscript files
for the new sim_objects and enums parameters, this will give them some
indication what's wrong, rather than the build just failing later.

Change-Id: Ic1933f7b9dfff7dd7e403c6c84f1f510c8ee8c72
Maintainer: Gabe Black <>
Tested-by: kokoro <>
Reviewed-by: Andreas Sandberg <>
4 files changed