Make "make clean" remove chicken-config.h

[Mario Domenech Goulart]

The fact that make clean doesn't remove chicken-config.h is a recurrent source of tricky-to-debug installation issues.

This ticket is about making make clean remove chicken-config.h. Since preserving chicken-config.h can be useful for developers, it'd be good to have a variable to indicate that chicken-config.h is to be preserved when processing the clean target (e.g., PRESERVE_CONFIG).

[Mario Domenech Goulart]

Suggestion by Lassi Kortela (received via e-mail):

Or a separate make devclean target which preserves the config, and
make clean would do a devclean plus some more things like removing
the config? That way no variables would be required, though it's easy
to type make clean out of habit since it's a standard target.

[Mario Domenech Goulart]

As discussed with Felix on IRC, we agreed that simply making clean remove build configuration files would do the trick, so devclean won't be necessary. With that change, disclean became redundant, as it did what clean now does, so it has been dropped.

Patch has been submitted to chicken-hackers: ​https://lists.nongnu.org/archive/html/chicken-hackers/2021-08/msg00019.html