freebsd.filterSource: use a less featureful rsync

By adding fewer dependencies, the FreeBSD native bootstrap tarball
becomes lighter.

pkgs/os-specific/bsd/freebsd/pkgs/filterSource.nix

@@ -18,6 +18,17 @@ let
     lib.concatMapStringsSep "\n" (path: "/${path}") sortedPaths
   );
 in
-runCommand "${pname}-filtered-src" { nativeBuildInputs = [ pkgsBuildBuild.rsync ]; } ''
-  rsync -a -r --files-from=${filterText} ${source}/ $out
-''
+runCommand "${pname}-filtered-src"
+  {
+    nativeBuildInputs = [
+      (pkgsBuildBuild.rsync.override {
+        enableZstd = false;
+        enableXXHash = false;
+        enableOpenSSL = false;
+        enableLZ4 = false;
+      })
+    ];
+  }
+  ''
+    rsync -a -r --files-from=${filterText} ${source}/ $out
+  ''