clippy: add rustc.llvm to buildInputs

The Hydra build [1] failed because it was unable to link to `LLVM9`; add
`llvmShared` to `passthru` in order to stay up to date with required
LLVM versions. Also quote the homepage URLs, since that's preferred.

[1] https://hydra.nixos.org/build/112989779/nixlog/1

pkgs/development/compilers/rust/clippy.nix

@@ -11,7 +11,7 @@ rustPlatform.buildRustPackage {
   # changes hash of vendor directory otherwise
   dontUpdateAutotoolsGnuConfigScripts = true;
 
-  buildInputs = [ rustc ] ++ stdenv.lib.optionals stdenv.isDarwin [ Security ];
+  buildInputs = [ rustc rustc.llvm ] ++ stdenv.lib.optionals stdenv.isDarwin [ Security ];
 
   # fixes: error: the option `Z` is only accepted on the nightly compiler
   RUSTC_BOOTSTRAP = 1;
@@ -26,7 +26,7 @@ rustPlatform.buildRustPackage {
   '';
 
   meta = with stdenv.lib; {
-    homepage = https://rust-lang.github.io/rust-clippy/;
+    homepage = "https://rust-lang.github.io/rust-clippy/";
     description = "A bunch of lints to catch common mistakes and improve your Rust code";
     maintainers = with maintainers; [ basvandijk ];
     license = with licenses; [ mit asl20 ];

pkgs/development/compilers/rust/rustc.nix

@@ -155,8 +155,10 @@ in stdenv.mkDerivation rec {
 
   requiredSystemFeatures = [ "big-parallel" ];
 
+  passthru.llvm = llvmShared;
+
   meta = with stdenv.lib; {
-    homepage = https://www.rust-lang.org/;
+    homepage = "https://www.rust-lang.org/";
     description = "A safe, concurrent, practical language";
     maintainers = with maintainers; [ madjar cstrahan globin havvy ];
     license = [ licenses.mit licenses.asl20 ];