x11/freerdp: default /sound to sndio

'xfreerdp /sound ...' and more importantly remmina configurations with
the GUI knob set to local sound will both use the "fake" backend by default.

'xfreerdp /sound:sys:sndio ...' and "sys:sndio" added as parameter in
remmina fix sound, but that takes a little digging (remmina's GUi tooltip
does not mention sndio).

As per xfreerdp(1):
/sound[:[sys:sys,][dev:dev,][format:format,][rate:rate,][channel:channel,][latency:latency,][quality:quality]],
/audio[:[sys:sys,][dev:dev,][format:format,][rate:rate,][channel:channel,][latency:latency,][quality:quality]]
Audio output (sound)

The patch only defaults to sndio if exactly "/sound" was used, i.e.
any "/sound:..." invocation has the same effect as before.

I'm new to RDP from OpenBSD and thought sndio would be a saner default.

Feedback? Objection? OK?

Index: Makefile
===================================================================
RCS file: /cvs/ports/x11/freerdp/Makefile,v
diff -u -p -r1.67 Makefile
--- Makefile 27 Sep 2023 20:37:05 -0000 1.67
+++ Makefile 2 Feb 2024 05:07:24 -0000
@@ -2,6 +2,7 @@ COMMENT = client for Microsoft RDP (rem
DISTNAME = freerdp-2.11.2
DPB_PROPERTIES = parallel
CATEGORIES = x11 net
+REVISION = 0

SHARED_LIBS += freerdp-client2 1.1
SHARED_LIBS += freerdp2 3.0
Index: patches/patch-channels_rdpsnd_client_rdpsnd_main_c
===================================================================
RCS file: patches/patch-channels_rdpsnd_client_rdpsnd_main_c
diff -N patches/patch-channels_rdpsnd_client_rdpsnd_main_c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ patches/patch-channels_rdpsnd_client_rdpsnd_main_c 2 Feb 2024 05:57:05 -0000
@@ -0,0 +1,15 @@
+Default /sound (without parameters) to :sys:sndio
+
+Index: channels/rdpsnd/client/rdpsnd_main.c
+--- channels/rdpsnd/client/rdpsnd_main.c.orig
++++ channels/rdpsnd/client/rdpsnd_main.c
+@@ -966,7 +966,8 @@ static UINT rdpsnd_process_addin_args(rdpsndPlugin* rd
+ }
+ CommandLineSwitchEnd(arg)
+ } while ((arg = CommandLineFindNextArgumentA(arg)) != NULL);
+- }
++ } else
++ rdpsnd_set_subsystem(rdpsnd, "sndio"); /* default to sndio(7) not fake backend */
+
+ return CHANNEL_RC_OK;
+ }