sox: musl does not support pipe rewind

Disable the pipe rewind related feature since musl has no support for it.

pkgs/applications/misc/audio/sox/0001-musl-rewind-pipe-workaround.patch

···
+From e7446c9bcb47674c9d0ee3b5bab129e9b86eb1c9 Mon Sep 17 00:00:00 2001
+From: Walter Franzini <[e-mail]>
+Date: Fri, 7 Jun 2019 17:57:11 +0200
+Subject: [PATCH] musl does not support rewind pipe, make it build anyway
+
+---
+ src/formats.c | 1 -
+ 1 file changed, 1 deletion(-)
+
+diff --git a/src/formats.c b/src/formats.c
+index f3efe764..477bf451 100644
+--- a/src/formats.c
++++ b/src/formats.c
+@@ -424,7 +424,6 @@ static void UNUSED rewind_pipe(FILE * fp)
+   /* To fix this #error, either simply remove the #error line and live without
+    * file-type detection with pipes, or add support for your compiler in the
+    * lines above.  Test with cat monkey.wav | ./sox --info - */
+-  #error FIX NEEDED HERE
+   #define NO_REWIND_PIPE
+   (void)fp;
+ #endif
+-- 
+2.19.2
+

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

···
   # configure.ac uses pkg-config only to locate libopusfile
   nativeBuildInputs = optional enableOpusfile pkg-config;
 
+  patches = [ ./0001-musl-rewind-pipe-workaround.patch ];
+
   buildInputs =
     optional (enableAlsa && stdenv.isLinux) alsaLib ++
     optional enableLibao libao ++