llvmPackages: 14.0.6 -> 17.0.6 for other platforms

This is supposed to be kept at the latest LLVM version — it used to be
set to llvmPackages_latest before I moved that to aliases.nix.

pkgs/top-level/all-packages.nix

@@ -16635,7 +16635,8 @@ with pkgs;
       else if platform.isAndroid then 12
       else if platform.isLinux then 16
       else if platform.isWasm then 16
-      else 14;
+      # For unknown systems, assume the latest version is required.
+      else 17;
     # 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.