pkg/51443: mpv adjusts volume badly (it's assuming netbsd has OSSv4)

[coypu%sdf.org@localhost]

>Number:         51443
>Category:       pkg
>Synopsis:       mpv adjusts volume badly (it's assuming netbsd has OSSv4)
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Aug 24 09:05:00 +0000 2016
>Originator:     coypu
>Release:        NetBSD 7.99.36, pkgsrc-2016Q3 (-current now)
>Organization:
>Environment:
NetBSD  7.99.36 NetBSD 7.99.36 (GENERIC.201608232230Z) amd64

>Description:
mpv uses #if SNDCTL_DSP_GETPLAYVOL as a test for OSSv4.
if it is defined (it is, for netbsd) then it will have a volume adjustment knob.
for whatever reason, the calls it makes result in having outputs.master
set to 254,0 for one video, then 100,0 for next.

it also says:
[ao/oss] Can't set audio device to s32 output.
[ao/oss] Unknown/Unsupported OSS format: 0x1.
[ao/oss] Can't set audio device to s24 output.
[ao/oss] Unknown/Unsupported OSS format: 0x1.

perhaps something is not sensible with the calls used to adjust volume in netbsd.
but I don't know what calls it attempts to make.
>How-To-Repeat:

>Fix:
Workaround:

Index: Makefile
===================================================================
RCS file: /cvsroot/pkgsrc/multimedia/mpv/Makefile,v
retrieving revision 1.37
diff -u -r1.37 Makefile
--- Makefile	17 Aug 2016 00:06:44 -0000	1.37
+++ Makefile	24 Aug 2016 08:49:41 -0000
@@ -14,6 +14,13 @@
 # needs sem_timedwait(3)
 NOT_FOR_PLATFORM=	NetBSD-[1-6]*-*
 
+# NetBSD doesn't actually have OSSv4, and this define is the test
+# for it. Results in randomly adjusting volume on new video to silly
+# values.
+.  if !empty(MACHINE_PLATFORM:MNetBSD-*)
+CFLAGS+=-USNDCTL_DSP_GETPLAYVOL
+.  endif
+
 BUILD_DEPENDS+=	${PYPKGPREFIX}-docutils>=0.12:../../textproc/py-docutils
 # ${WRKSRC}/bootstrap.py mentions needed version
 BUILD_DEPENDS+=	waf>=1.8.12:../../devel/waf