libwbxml: fix build

pkgs/by-name/li/libwbxml/package.nix

···
   lib,
   cmake,
   expat,
+  check,
+  pkg-config,
 }:
 
 stdenv.mkDerivation rec {
···
     sha256 = "sha256-yy8+CyNKXuttCmxRxH/XptIloDklto4f5Zg0vnwnneY=";
   };
 
-  nativeBuildInputs = [ cmake ];
+  nativeBuildInputs = [
+    cmake
+    pkg-config
+    check
+  ];
   buildInputs = [ expat ];
 
-  postPatch = ''
-    sed -i 's/^SET.*$//' cmake/CMakeLists.txt
-  '';
-
   meta = with lib; {
     homepage = "https://github.com/libwbxml/libwbxml";
     description = "WBXML Library (aka libwbxml) contains a library and its associated tools to Parse, Encode and Handle WBXML documents";
     maintainers = with maintainers; [ mh ];
-    platforms = platforms.linux;
+    platforms = platforms.unix;
     license = licenses.lgpl21Plus;
   };
 }