sox: remove ? null from inputs, cleanup meta, enable pulseaudio only on linux

pkgs/applications/misc/audio/sox/default.nix

···
 , pkg-config
 , CoreAudio
 , enableAlsa ? true
-, alsa-lib ? null
+, alsa-lib
 , enableLibao ? true
-, libao ? null
+, libao
 , enableLame ? config.sox.enableLame or false
-, lame ? null
+, lame
 , enableLibmad ? true
-, libmad ? null
+, libmad
 , enableLibogg ? true
-, libogg ? null
-, libvorbis ? null
+, libogg
+, libvorbis
 , enableOpusfile ? true
-, opusfile ? null
+, opusfile
 , enableFLAC ? true
-, flac ? null
+, flac
 , enablePNG ? true
-, libpng ? null
+, libpng
 , enableLibsndfile ? true
-, libsndfile ? null
+, libsndfile
 , enableWavpack ? true
-, wavpack ? null
+, wavpack
   # amrnb and amrwb are unfree, disabled by default
 , enableAMR ? false
-, amrnb ? null
-, amrwb ? null
-, enableLibpulseaudio ? true
-, libpulseaudio ? null
+, amrnb
+, amrwb
+, enableLibpulseaudio ? stdenv.isLinux
+, libpulseaudio
 }:
-
-with lib;
 
 stdenv.mkDerivation rec {
   pname = "sox";
···
   };
 
   # configure.ac uses pkg-config only to locate libopusfile
-  nativeBuildInputs = optional enableOpusfile pkg-config;
+  nativeBuildInputs = lib.optional enableOpusfile pkg-config;
 
   patches = [ ./0001-musl-rewind-pipe-workaround.patch ];
 
   buildInputs =
-    optional (enableAlsa && stdenv.isLinux) alsa-lib ++
-    optional enableLibao libao ++
-    optional enableLame lame ++
-    optional enableLibmad libmad ++
-    optionals enableLibogg [ libogg libvorbis ] ++
-    optional enableOpusfile opusfile ++
-    optional enableFLAC flac ++
-    optional enablePNG libpng ++
-    optional enableLibsndfile libsndfile ++
-    optional enableWavpack wavpack ++
-    optionals enableAMR [ amrnb amrwb ] ++
-    optional enableLibpulseaudio libpulseaudio ++
-    optional (stdenv.isDarwin) CoreAudio;
+    lib.optional (enableAlsa && stdenv.isLinux) alsa-lib
+    ++ lib.optional enableLibao libao
+    ++ lib.optional enableLame lame
+    ++ lib.optional enableLibmad libmad
+    ++ lib.optionals enableLibogg [ libogg libvorbis ]
+    ++ lib.optional enableOpusfile opusfile
+    ++ lib.optional enableFLAC flac
+    ++ lib.optional enablePNG libpng
+    ++ lib.optional enableLibsndfile libsndfile
+    ++ lib.optional enableWavpack wavpack
+    ++ lib.optionals enableAMR [ amrnb amrwb ]
+    ++ lib.optional enableLibpulseaudio libpulseaudio
+    ++ lib.optional stdenv.isDarwin CoreAudio;
 
-  meta = {
+  meta = with lib; {
     description = "Sample Rate Converter for audio";
     homepage = "http://sox.sourceforge.net/";
-    maintainers = [ lib.maintainers.marcweber ];
-    license = if enableAMR then lib.licenses.unfree else lib.licenses.gpl2Plus;
-    platforms = lib.platforms.linux ++ lib.platforms.darwin;
+    maintainers = with maintainers; [ marcweber ];
+    license = if enableAMR then licenses.unfree else licenses.gpl2Plus;
+    platforms = platforms.unix;
   };
 }