build: Replace $(AT) with .SILENT

[dgoncharov]

This reduces the amount of syntax noise in the makefiles.
Setting V=1 still enables verbose logging.

The only noticeable difference in behavior is that, unless V=1 is specified, make won't print its own messages like
make: Nothing to be done for 'all', make: 'all' is up to date, or touch , if -t is specified.

[hebasto]

s/.SILENCE/.SILENT/ in the PR name?

[hebasto]

On master, for debugging purpose one could easy enable echoing for particular lines in a recipe by removing $(AT).

How to achieve the same goal with this PR?

[DrahtBot]

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

Conflicts

Reviewers, this pull request conflicts with the following ones:

• #22811 (build: Fix depends build system when working with subtargets by hebasto)
• #22126 (build: Disable make builtin rules. by dgoncharov)
• #21995 (build: Make built dependency packages reproducible by hebasto)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

[dgoncharov]

s/.SILENCE/.SILENT/ in the PR name?

Indeed.

[dgoncharov]

On master, for debugging purpose one could easy enable echoing for particular lines in a recipe by removing $(AT).

How to achieve the same goal with this PR?

You'd need to do the opposite. Which is to add @ in front of those lines which you want to silence. That'd be inconvenient.

You can do something similar though. If you are willing to modify the makefile, then you can add .SILENT: and make it depend on targets which you want to silence.

Some of these recipes run a sequence of shell commands bound together through && and ||. You won't be able to selectively enable or disable echoing parts of these either on master or on this branch. E.g. fetch_file_inner. These recipes would need to be written in a more conventional make style. Without && and ||, but rather on different recipe lines.

[dgoncharov]

On master all the recipe lines have $(AT), on the branch none of them has.
This allows to come up with the opposite use case.

On the branch, for debugging purpose one could easy disable echoing for particular lines in a recipe by adding @.
You see, depending on how many lines you need to modify, could be easier on master or this branch.

[dongcarl]

Can verify that .SILENT exists for both GNU Make and BSD Make (the only two UNIX implementations)

[dgoncharov]

Can verify that .SILENT exists for both GNU Make and BSD Make (the only two UNIX implementations)

.SILENT exists in other make implementations as well as in posix. .SILENT was even supported by the very first make of Stuart Feldman.

[dgoncharov]

i merged master onto this branch, resolved the coflict and pushed to my fork.
Is anything else needed in regards to the "needs rebase" label?

[fanquake]

Is anything else needed in regards to the "needs rebase" label?

No, the label is removed by the bot, however you need to get rid of the merge commit here.

[maflcko]

The following should do a proper rebase:

git reset --hard 04f41bbca0e462b70b9e5aa4115adf37db43735a
git rebase bitcoin-core/master

[dgoncharov]

Thanks, rebased.

[laanwj]

Tested ACK 8494dca
Depends builds without and with V=1 work after this.