Bug 1670917 - Upstream build system and other bits from freebsd-ports. r=cubeb-reviewers,chunmin

This is the first two chunks in ed3dd55916/www/firefox/files/patch-cubeb-oss, from From: jbeich <jbeich@FreeBSD.org>. The rest of this patch file is now upstream.

This allows OSS users to drop a patch downstream.

Differential Revision: https://phabricator.services.mozilla.com/D93362

dom/media/CubebUtils.cpp

@@ -125,8 +125,9 @@ int sInCommunicationCount = 0;
 const char kBrandBundleURL[] = "chrome://branding/locale/brand.properties";
 
 const char* AUDIOSTREAM_BACKEND_ID_STR[] = {
-    "jack",  "pulse",       "alsa",  "audiounit", "audioqueue", "wasapi",
-    "winmm", "directsound", "sndio", "opensl",    "audiotrack", "kai"};
+    "jack",   "pulse",      "alsa",        "audiounit", "audioqueue",
+    "wasapi", "winmm",      "directsound", "sndio",     "opensl",
+    "oss",    "audiotrack", "kai"};
 /* Index for failures to create an audio stream the first time. */
 const int CUBEB_BACKEND_INIT_FAILURE_FIRST =
     ArrayLength(AUDIOSTREAM_BACKEND_ID_STR);

media/libcubeb/src/moz.build

@@ -40,6 +40,12 @@ if CONFIG['MOZ_JACK']:
     ]
     DEFINES['USE_JACK'] = True
 
+if CONFIG['OS_ARCH'] in ('DragonFly', 'FreeBSD', 'SunOS'):
+    SOURCES += [
+        'cubeb_oss.c',
+    ]
+    DEFINES['USE_OSS'] = True
+
 if CONFIG['OS_ARCH'] == 'OpenBSD':
     SOURCES += [
         'cubeb_sndio.c',