Add audio utility programs.
The audio device can be inspected and changed by audioctl,
and the mixer device by mixerctl. The command syntax was
inspired by sysctl.

Resort sections to canonical order

Fix-up syntax after wizd.

branches: 1.23.4; 1.23.8; 1.23.10;
Fix typo in Dd argument.

For binary controls, ++ and -- toggle between on and off.

branches: 1.21.2;
Convert TNF licenses to new 2 clause variant

branches: 1.20.20;
Two improvements, from a diff from jmc@openbsd.

Mention mixerctl.conf in FILES and SEE ALSO. While here, tidy up some
sentences. Bump date. Closes my own PR misc/23516.

Fix typo about which mixer device is used.

Allow using '+=number' (resp. -=number) to produce the same effect as
several '++' (resp. '--'). Suggested by David Brownlee in tech-kern.

.Nm does not need a dummy argument ("") before punctuation or
for correct formatting of the SYNOPSIS any longer.

Ispell. Begin new sentences on a new line.

Use '-d' rather than '-f' for specification of alternative
mixer or audioctl device. The support for '-f' is kept for compatibility
for now.

Sort sections.

Whitespace cleanup.

Add ++ and -- for changing mixer controls. They bump the value to
the next possible setting.

Add missing .El line.

Use audio and mixer devices with unit numbers. Also allow the devices
without unit numbers of a compatibility option is set. Fixes PR 5991.

Fix typo.

Add some more explanatory text.

Chnage the name of the environment variables just introduced.

dd environment variable for default mixer device.

fix up .Nm usage

Fix tipo inherited from old version of TNF copyright template.

Add HISTORY section.

Add audio utility programs.
The audio device can be inspected and changed by audioctl,
and the mixer device by mixerctl. The command syntax was
inspired by sysctl.

mixerctl: add colon after 'Usage', add space after comma

fix error messages, usage, add static, more checks for ioctl, KNF

Provide a clipping function and use it to prevent setting values out of bounds.
(from RVP)

Generate usage error for bad usage, before attempting any other operations.
This means that "mixerctl" (no args) will generate a usage msg, even when
/dev/mixer cannot be opened (or any other device given via -d or $MIXERDEVICE)

While here, get rid of "goto usage" replacing the usage: with a
static inline void __dead function... The compiler ought to optimise
the calls into essentially the same code as existed with the goto version,
but this is much cleaner.

Also, mixerctl falls back on /dev/mixer0 if /dev/mixer cannot be opened.
(that is old code - probably from when /dev/mixer was first added)

It used to do that when called as mixerctl -d /dev/mixer or with
"MIXERDEVICE=/dev/mixer mixerctl...". No longer. Now the fallback (which
is probably obsolete now anyway) only happens when the user doesn't specify
any mixer device (by either method) and the default of /dev/mixer is used.
In other cases, only the device specified is tried.

branches: 1.26.12; 1.26.16;
Fix indent and style. no functional changes.

Avoid SEGV even if audio device has no mixer features.
Fix PR/47003

branches: 1.24.6; 1.24.12;
Compare strings with strcmp(), not ==.
Part of PR 41255 from Kurt Lidl.

fix -Wcast-qual issues

branches: 1.22.8;
Remove clause 3 and 4 from TNF licenses

branches: 1.21.32;
Allow using '+=number' (resp. -=number) to produce the same effect as
several '++' (resp. '--'). Suggested by David Brownlee in tech-kern.

netbsd.org->NetBSD.org

asprintf is safer. add error trap for malloc failure

Add NetBSD RCS Ids.

Use _PATH_SOUND etc, all fall back to _PATH_SOUND0 (etc.) if that fails.

Use '-d' rather than '-f' for specification of alternative
mixer or audioctl device. The support for '-f' is kept for compatibility
for now.

Add ++ and -- for changing mixer controls. They bump the value to
the next possible setting.

Make the copyright header conform to the NetBSD template.

Fix thinko in last commit.

Use audio and mixer devices with unit numbers. Also allow the devices
without unit numbers of a compatibility option is set. Fixes PR 5991.

Chnage the name of the environment variables just introduced.

dd environment variable for default mixer device.

Print unit if verbose.

Test for valid mixer class the right way. From PR 4279.

Fix tipo inherited from old version of TNF copyright template.

Get rid of warnings.

Print class correctly for linked fields.

Improve printing of values when changing a variable.

Fix bugs when recording source is a set.

Fix some buglets and clean up a little.

Add audio utility programs.
The audio device can be inspected and changed by audioctl,
and the mixer device by mixerctl. The command syntax was
inspired by sysctl.