llvmPackages: llvmPackages_{16,18} -> llvmPackages_19

pkgs/top-level/all-packages.nix

···
   libllvm = llvmPackages.libllvm;
   llvm-manpages = llvmPackages.llvm-manpages;
 
-  # Please remove all this logic when bumping to LLVM 19 and make this
-  # a simple alias.
-  llvmPackages = let
-    # This returns the minimum supported version for the platform. The
-    # assumption is that or any later version is good.
-    choose = platform: if platform.isDarwin then 16 else 18;
-    # We take the "max of the mins". Why? Since those are lower bounds of the
-    # supported version set, this is like intersecting those sets and then
-    # taking the min bound of that.
-    minSupported = toString (lib.trivial.max (choose stdenv.hostPlatform) (choose
-      stdenv.targetPlatform));
-  in pkgs.${"llvmPackages_${minSupported}"};
+  llvmPackages = llvmPackages_19;
 
   inherit (rec {
     llvmPackagesSet = recurseIntoAttrs (callPackages ../development/compilers/llvm { });