treewide: All the linker to be chosen independently

This will begin the process of breaking up the `useLLVM` monolith. That
is good in general, but I hope will be good for NetBSD and Darwin in
particular.

Co-authored-by: sterni <sternenseemann@systemli.org>

pkgs/os-specific/windows/default.nix

@@ -19,7 +19,7 @@ lib.makeScope newScope (self: with self; {
 
   crossThreadsStdenv = overrideCC crossLibcStdenv
     (if stdenv.hostPlatform.useLLVM or false
-     then buildPackages.llvmPackages_8.lldClangNoLibcxx
+     then buildPackages.llvmPackages_8.clangNoLibcxx
      else buildPackages.gccCrossStageStatic.override (old: {
        bintools = old.bintools.override {
          libc = libcCross;