SCons: Add object_prefix option

[maiself]

Add object_prefix as an scons option to add a custom prefix to all generated object files, via the OBJPREFIX and SHOBJPREFIX environment variables.

This is useful for instance to hide object files on unix-like systems and make the source directories less cluttered by setting object_prefix = '.' in custom.py.

[akien-mga]

This is useful for instance to hide object files on unix-like systems and make the source directories less cluttered by setting object_prefix = '.' in custom.py.

That's a pretty niche use case, I'm not sure it's worth adding an option just for this. Most IDEs will not show you the object files so the clutter shouldn't be a problem for development. And hiding several GBs worth of object files doesn't strike me as a good workflow to encourage.

[maiself]

Object files are intermediate artifacts, not unlike imports in .godot or a browser cache, and usually don't need to be interacted with. I'm not sure what workflow benefits from having them visible alongside source files.

scons lacks out of tree builds, prefixing object files with . is the easiest way to deal with the clutter.

I was hoping it might be useful for developers like myself who develop without an IDE. Such workflow maybe niche, but I prefer simplicity.

Alternative to this patch is hacking Environment via site_init.py which is not so simple and feels fragile.

Three lines for an option, and not a default one as to avoid affecting existing workflows, hardly seems like much to add for the gained simplicity.

I'm not extremely attached to this patch, and am fine with it not being accepted, but hope you can see how it could be beneficial and give it consideration.

[aaronfranke]

It's true that this would mainly benefit people without an IDE. Really, I would recommend getting one, VS Code is free and allows you to hide .o and .a files. But if we want to support developing without an IDE, it would be nice to hide these files:

[jukrb0x]

Indeed, CLion shows the .o files in the source tree, even though the Project Source View does help but it only shows the cpp source files such as .cpp and .h, the project requires other files like markdown, python, and configurations that are also needed in the IDEs.

In my mind, these output files can be put in separation from the source files, such as in a ${source_dir}/generated/*.o.

and this fix does help!

[dsnopek]

This is such a small change, and wouldn't require much maintenance, since the OBJPREFIX and SHOBJPREFIX come from scons. If folks find this useful, why not?

[akien-mga]

Seems fine.

[akien-mga]

Needs rebase.

[akien-mga]

Thanks!