Do not write fusesoc.log by default

[imphil]

Fusesoc by default writes a file 'fusesoc.log' into the working directory. Even though this is common for many EDA tools, I suggest removing this functionality by default.

Why?

• Having two fusesoc runs in the same directory results in an "interleaved" fusesoc.log file, essentially a useless one.
• It's very uncommon behavior for any "non-EDA" tool.

Two ideas how to resolve this:

• Write the fusesoc.log file to the build directory (build/DESIGNNAME/...)
• Don't write a fusesoc.log file unless instructed so by e.g. a command line option (e.g. --logfile=fusesoc.log)

[olofk]

A thousand times yes!! It has annoyed me so many times. Especially since I hate when other EDA tools leave unnecessary files around. I just never got down to fixing it. Just adding an optional command-line option is enough I would say

[wallento]

A first mitigation is to add the pid to the filename or so, but overall I am the third in the gang of haters of tools writing files without me asking for it..

[olofk]

Yeah, just leave it to the user to specify a unique filename if they need that