python3Packages.llvmlite: make it statically link to llvm

Llvmlite doc says that they link to llvm statically, but it's not. Check

- numba/llvmlite#1027.
- https://github.com/numba/llvmlite/blob/ca123c3ae2a6f7db865661ae509862277ec5d692/docs/source/faqs.rst#why-static-linking-to-llvm

This behavior causes problems when python uses another version of llvm,
for example, mesa llvmpipe. This PR force llvmlite statically link to llvm.

Besides, this PR also use llvm as buildInputs rather than nativeBuildInputs
since it's a library that llvmlite use rather than a part of build system.

This PR also cleans outdated patches.

pkgs/development/python-modules/llvmlite/default.nix

@@ -6,12 +6,14 @@
   isPyPy,
   pythonAtLeast,
 
-  # build-system
-  llvm,
   setuptools,
 
   # tests
   pytestCheckHook,
+  llvm,
+  libxml2,
+
+  withStaticLLVM ? true,
 }:
 
 buildPythonPackage rec {
@@ -28,32 +30,27 @@ buildPythonPackage rec {
     hash = "sha256-5QBSRDb28Bui9IOhGofj+c7Rk7J5fNv5nPksEPY/O5o=";
   };
 
-  nativeBuildInputs = [
-    llvm
-    setuptools
-  ];
+  build-system = [ setuptools ];
 
-  postPatch = ''
-    substituteInPlace llvmlite/tests/test_binding.py \
-      --replace-fail "test_linux" "nope"
+  buildInputs = [ llvm ] ++ lib.optionals withStaticLLVM [ libxml2.dev ];
+
+  postPatch = lib.optionalString withStaticLLVM ''
+    substituteInPlace ffi/build.py --replace-fail "--system-libs --libs all" "--system-libs --libs --link-static all"
   '';
 
   # Set directory containing llvm-config binary
-  preConfigure = ''
-    export LLVM_CONFIG=${llvm.dev}/bin/llvm-config
-  '';
+  env.LLVM_CONFIG = "${llvm.dev}/bin/llvm-config";
+
+  nativeCheckInputs = [ pytestCheckHook ];
 
-  nativeCheckInputs = [
-    pytestCheckHook
-  ];
   # https://github.com/NixOS/nixpkgs/issues/255262
   preCheck = ''
     cd $out
   '';
 
   __impureHostDeps = lib.optionals stdenv.isDarwin [ "/usr/lib/libm.dylib" ];
 
-  passthru.llvm = llvm;
+  passthru = lib.optionalAttrs (!withStaticLLVM) { inherit llvm; };
 
   meta = {
     changelog = "https://github.com/numba/llvmlite/blob/v${version}/CHANGE_LOG";