Makefile: Keep output artifacts when rebuilding

[grische]

When doing a new build or a rebuild, all previous artifacts are deleted even if the new build fails. Replacing mv with rsync allows preserving previous artifacts.

[goligo]

Honestly, I don't like this - just complicates things, if old build artifacts are kept. You can no longer distinguish, whether they are from the current or last build, whether they include your latest change or they don't.

If you want to keep old build output, make a local script to copy them somewhere else.

[grische]

Each build has both a timestamp as well as it uses the git hash in its name. I don't see how you be struggling to distinguish new and old builds, when builds take always more than a few minutes.

In case of identical names, successful builds will overwrite existing artifacts. If a build failed, you would be able to see it both in the log messages, the return code or the timestamp of the last build.

[goligo]

Seriously, I think this is wrong. I don't want to keep old build output. If you really want this, hide it behind a build option and keep the default as is.

[Djfe]

in Aachen we use environment variables now and only have one output folder for Gluon instead.
no mv or rsync needed. This way you have to move outputfolders if you want to keep old builds.

we set

GLUON_SITEDIR := ..  # can only be set in makefile, we don't need to create a symbolic link anylonger
GLUON_OUTPUTDIR := $(GLUON_SITEDIR)/output  # we are setting this in our site.mk

https://gluon.readthedocs.io/en/latest/user/getting_started.html

also we have a different output folder, for when we build single devices now:

ifdef GLUON_DEVICES
    GLUON_OUTPUTDIR := $(GLUON_SITEDIR)/devices
endif

(we stop output-clean, when GLUON_DEVICES is set)

[GoliathLabs]

in Aachen we use environment variables now and only have one output folder for Gluon instead. no mv or rsync needed. This way you have to move outputfolders if you want to keep old builds.

we set

GLUON_SITEDIR := ..  # can only be set in makefile, we don't need to create a symbolic link anylonger
GLUON_OUTPUTDIR := $(GLUON_SITEDIR)/output  # we are setting this in our site.mk

https://gluon.readthedocs.io/en/latest/user/getting_started.html

also we have a different output folder, for when we build single devices now:

ifdef GLUON_DEVICES
    GLUON_OUTPUTDIR := $(GLUON_SITEDIR)/devices
endif

(we stop output-clean, when GLUON_DEVICES is set)

@grische what do you think?