git-arc: Make patch with reviewers more portable

[jlduran]

Summary

Avoid an ArcanistUsageException:

Provide method parameters on stdin as a JSON blob.

Due to an invalid JSON input on strict POSIX-compliant shells (macOS):

echo '{
        "constraints": {"phids": [-n,"PHID-USER-xxx",]}
      }'                          ^^^               ^

Change the non-portable "echo -n" to a printf.

[markj]

I see a couple of other uses of echo -n, in gitarc__list().

[jlduran]

Fix other occurrences of "echo -n" while here.

[0mp]

I'll commit it soon.

[des]

tools/tools/git/git-arc.sh

331

you can just use echo here, the shell will strip the newline.

[jlduran]

tools/tools/git/git-arc.sh

331

Yes, the problem I see with using echo is that the trailing new line will also be translated to a ,, as it is also considered a [:space:]:

% userids="emaste imp markj 0mp"
% echo "$userids" | tr '[:space:]' ','
emaste,imp,markj,0mp,%
                    ^extra ','
% printf "%s" "$userids" | tr '[:space:]' ','
emaste,imp,markj,0mp%

[des]

tools/tools/git/git-arc.sh

331

Use [:blank:] instead.

[jlduran]

Please, feel free to commit the changes from that branch if you should consider so:
https://github.com/jlduran/freebsd-src/tree/fix-git-arc-consolidated

I do not yet have the appropriate permissions to do it.

tools/tools/git/git-arc.sh

331

Given this review has already been committed, present the suggestion on a separate patch:
https://github.com/jlduran/freebsd-src/commit/2c542e64d49252427c944ea43b2fc4eb35ad802c

[emaste]

I do not yet have the appropriate permissions to do it.

I believe everything should be set now.

[jlduran]

In D46781#1079099, @emaste wrote:

I do not yet have the appropriate permissions to do it.

I believe everything should be set now.

Thank you!