Shorten path for SUB_VENV and define it only on the first make level

[stweil]

There is no need for the additional directory "local" (which can
also be confused with "locale" on the same level).

Signed-off-by: Stefan Weil sw@weilnetz.de

[stweil]

This is also part of pull request #295.

[bertsky]

Fine with me.

[kba]

We should provide a migration script/makefile target, otherwise people with a local installation will have gigabytes of obsolete data in /local/sub-venv, won't they?

[stweil]

Do you think that people reuse their local venvs? I personally don't do so because it does not really work good to run incremental builds. Typically I create fresh venvs with the date in the name and run fresh builds. And from time to time I remove the old venvs.

A notice in the release notes would be sufficient in my opinion.

[bertsky]

A notice in the release notes would be sufficient in my opinion.

I concur. (Migrating venvs is not possible BTW – FS paths are fixed.)

[kba]

Do you think that people reuse their local venvs?

They do, sometimes even with a weekly cronjob. Just yesterday I told @lena-hinrichsen that git pull; make all should be enough after an update. But we can change that of course and tell people to build from scratch for every new release.