sofia_sip: fix darwin build

pkgs/development/libraries/sofia-sip/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchFromGitHub, glib, openssl, pkg-config, autoreconfHook }:
+{ lib, stdenv, fetchFromGitHub, glib, openssl, pkg-config, autoreconfHook, SystemConfiguration }:
 
 stdenv.mkDerivation rec {
   pname = "sofia-sip";
@@ -11,13 +11,13 @@ stdenv.mkDerivation rec {
     sha256 = "sha256-qMgZpLo/BHGJbJ0DDN8COHAhU3ujWgVK9oZOnnMwKas=";
   };
 
-  buildInputs = [ glib openssl ];
+  buildInputs = [ glib openssl ] ++ lib.optional stdenv.isDarwin SystemConfiguration;
   nativeBuildInputs = [ autoreconfHook pkg-config ];
 
   meta = with lib; {
     description = "Open-source SIP User-Agent library, compliant with the IETF RFC3261 specification";
     homepage = "https://github.com/freeswitch/sofia-sip";
-    platforms = platforms.linux;
+    platforms = platforms.unix;
     license = licenses.lgpl2;
   };
 }