add some pkgs for nix shell on linux

Author: ralexstokes

shell.nix

@@ -2,7 +2,10 @@
 with pkgs;
 mkShell {
   buildInputs = lib.optionals pkgs.stdenv.isLinux [
+    clang
     openssl
+    pkg-config
+    rustup
   ] ++ lib.optionals pkgs.stdenv.isDarwin [
     libiconv
     darwin.apple_sdk.frameworks.CFNetwork
@@ -12,4 +15,5 @@ mkShell {
     just
     mdbook
   ];
+  LIBCLANG_PATH = lib.optionals pkgs.stdenv.isLinux "${llvmPackages.libclang.lib}/lib";
 }