output/plugins/OSXOutputPlugin: add boost meson dependency

NEWS

@@ -9,6 +9,7 @@ ver 0.21.6 (not yet released)
   - opus: fix replay gain when there are no other tags
 * output
   - pulse: work around error with unusual channel count
+  - osx: fix build failure
 * playlist
   - flac: fix use-after-free bug
 * support abstract sockets on Linux

src/output/plugins/meson.build

@@ -76,7 +76,10 @@ if is_darwin
   audiounit_dep = declare_dependency(
     link_args: [
       '-framework', 'AudioUnit', '-framework', 'CoreAudio', '-framework', 'CoreServices',
-    ]
+    ],
+    dependencies: [
+      boost_dep,
+    ],
   )
 else
   audiounit_dep = dependency('', required: false)