echo(1): Replace errexit() with err(3)

[christos]

Summary

errexit() was supposed to be used in order to avoid
linking-in stdio, but err(3) is used in other parts of
the code already, so there's no reason to keep errexit().

[christos]

Remove progname.

[• hselasky]

Is this a revert of a previous commit? Then it should be mentioned.

[christos]

In D32501#733299, @hselasky wrote:

Is this a revert of a previous commit? Then it should be mentioned.

After a quick search through the commit history, I guess not.

[• hselasky]

Did you try "git blame bin/echo/echo.c" ?

Look at this:

commit 91b7d6dc5871f532b1a86ee76389a9bc348bdf58
Author: Diomidis Spinellis <[e-mail]>
Date:   Sat Oct 11 20:34:43 2003 +0000

    - Check and report write(2) errors.
    
    - Issue a single writev(2) call instead of multiple write(2)s.
      This change improves the inefficiencies introduced when echo
      went on an stdio diet.
    
    The following figures are for echoing 1000 arguments.
    original stdio-based echo:
            0.01 real         0.01 user         0.00 sys
    before:
            0.05 real         0.00 user         0.04 sys
    after:
            0.01 real         0.00 user         0.00 sys

Notes:
    svn path=/head/; revision=121010

[christos]

So errexit() was introduced when they wanted to avoid using
stdio. Now err(3) was already being used, so is this really a revert?
Also this cannot be a performance issue -- both errexit() and err(3)
would only get called once after all.

[christos]

Include whole file in diff.

[• hselasky]

Looks good. Let's see how it goes.