swiftPackages.*: build with the default LLVM version

pkgs/development/compilers/swift/compiler/default.nix

···
   '';
 
   # > clang-15-unwrapped: error: unsupported option '-fzero-call-used-regs=used-gpr' for target 'arm64-apple-macosx10.9.0'
-  hardeningDisable = lib.optional stdenv.hostPlatform.isAarch64 "zerocallusedregs";
+  # > clang-15-unwrapped: error: argument unused during compilation: '-fstack-clash-protection' [-Werror,-Wunused-command-line-argument]
+  hardeningDisable = lib.optionals stdenv.hostPlatform.isAarch64 [
+    "zerocallusedregs"
+    "stackclashprotection"
+  ];
 
   configurePhase = ''
     export SWIFT_SOURCE_ROOT="$PWD"

pkgs/development/compilers/swift/default.nix

···
   newScope,
   darwin,
   llvmPackages,
-  llvmPackages_15,
   overrideCC,
   overrideLibcxx,
 }:
 
 let
-  swiftLlvmPackages = llvmPackages_15;
+  swiftLlvmPackages = llvmPackages;
 
   self = rec {