musl-fts: init at 1.2.7

this is in service of getting elfutils building against musl-libc again.
the currently-included netbsd.fts package has a bunch of #define
collisions with current elfutils, so pulling this library in, which is
what both void and alpine linux do.

pkgs/os-specific/linux/musl-fts/default.nix

@@ -0,0 +1,25 @@
+{ lib, stdenv, fetchFromGitHub, autoreconfHook, pkg-config }:
+
+stdenv.mkDerivation rec {
+  pname = "musl-fts";
+  version = "1.2.7";
+
+  src = fetchFromGitHub {
+    owner = "void-linux";
+    repo = "musl-fts";
+    rev = "v${version}";
+    sha256 = "Azw5qrz6OKDcpYydE6jXzVxSM5A8oYWAztrHr+O/DOE=";
+  };
+
+  nativeBuildInputs = [ autoreconfHook pkg-config ];
+
+  enableParallelBuilding = true;
+
+  meta = with lib; {
+    homepage = "https://github.com/void-linux/musl-fts";
+    description = "An implementation of fts(3) for musl-libc";
+    platforms = platforms.linux;
+    license = licenses.bsd3;
+    maintainers = [ maintainers.pjjw ];
+  };
+}

pkgs/top-level/all-packages.nix

@@ -19489,6 +19489,8 @@ in
 
   musl = callPackage ../os-specific/linux/musl { };
 
+  musl-fts = callPackage ../os-specific/linux/musl-fts { };
+
   nushell = callPackage ../shells/nushell {
     inherit (darwin.apple_sdk.frameworks) AppKit Security;
   };