src/bin/echo/echo.c, branch releng/12.3

MFC r367136:

2020-11-02T01:34:43Z

Whitespace cleanup

MFC r367134:

2020-11-02T01:29:50Z

Remove superfluous `this` in comment PR: 250721 Submitted by: Hiroya EBINE

Convert `cap_enter() < 0 && errno != ENOSYS` to `caph_enter() < 0`.

2018-06-19T23:43:14Z

No functional change intended.

General further adoption of SPDX licensing ID tags.

2017-11-20T19:49:47Z

Mainly focus on files that use BSD 3-Clause license. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. Special thanks to Wind River for providing access to "The Duke of Highlander" tool: an older (2014) run over FreeBSD tree was useful as a starting point.

Renumber copyright clause 4

2017-02-28T23:42:47Z

Renumber cluase 4 to 3, per what everybody else did when BSD granted them permission to remove clause 3. My insistance on keeping the same numbering for legal reasons is too pedantic, so give up on that point. Submitted by: Jan Schaumann Pull Request: https://github.com/freebsd/freebsd/pull/96

Capsicumize some trivial stdio programs

2016-11-08T05:31:01Z

Trivially capsicumize some simple programs that just interact with stdio. This list of programs uses 'pledge("stdio")' in OpenBSD. No objection from: allanjude, emaste, oshogbo Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D8307

Mark functions as __dead2 in order to help the LLVM static checker

2008-08-04T01:25:48Z

understand which code paths aren't possible. This commit eliminates 117 false positive bug reports of the form "allocate memory; error out if pointer is NULL; use pointer".

/*- or .\"- or #- to begin license clauses.

2005-01-10T08:39:26Z

Remove clause 3 from the UCB licenses.

2004-04-06T20:06:54Z

OK'ed by: imp, core

- Check and report write(2) errors.

2003-10-11T20:34:43Z

- 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