Arduino.mk: Fix clean target declaration

[rzr]

Write clean: instead of clean::

This is needed on some systems

Change-Id: Ie9186b7c5b6920327846e42483f0299d42ce693b
Signed-off-by: Philippe Coval [email protected]

[sudar]

@rzr

Thanks for your Pull request.

@sej7278

Do you remember why we have an extra : for clean? Was it a typo?

[sej7278]

seems its pretty normal for make clean to have double colons, don't quite understand why but i'd rather not remove it without more justification than "This is needed on some systems" ;-)

https://www.gnu.org/software/make/manual/html_node/Double_002dColon.html

[sudar]

@sej7278

Thanks.

@rzr

Can you please give us more information about the exact issue that you have been facing because of the double colon?

[rzr]

I know that I had to change it , but I don't remember why...

[wingunder]

I know that I had to change it , but I don't remember why...

I guess you wanted to do one of the following:

• 'override' or 'replace', instead of 'extend' the clean-target.
• 'extend' the clean-target, but did not add 2 colons after your extended clean-target and ended up with an error.

This is why the clean target has a double colon: #239
By making it a single colon again, will prevent the user from "extending the actions during cleaning", and this will cause some chaos with some user-makefiles that do just that.

[sudar]

@wingunder

Thanks for the explanation. Totally makes sense.

@rzr

I am closing this without merging for the above reasons. Do re-open if you have more information.