llama-cpp: add bash completion

for the "llama-server" executable

pkgs/by-name/ll/llama-cpp/package.nix

@@ -3,6 +3,7 @@
   autoAddDriverRunpath,
   cmake,
   fetchFromGitHub,
+  installShellFiles,
   nix-update-script,
   stdenv,
 
@@ -89,6 +90,7 @@ effectiveStdenv.mkDerivation (finalAttrs: {
 
   nativeBuildInputs = [
     cmake
+    installShellFiles
     ninja
     pkg-config
   ]
@@ -151,6 +153,10 @@ effectiveStdenv.mkDerivation (finalAttrs: {
 
     mkdir -p $out/include
     cp $src/include/llama.h $out/include/
+
+  ''
+  + lib.optionalString (stdenv.buildPlatform.canExecute stdenv.hostPlatform) ''
+    installShellCompletion --cmd llama-server --bash <($out/bin/llama-server --completion-bash)
   ''
   + optionalString rpcSupport "cp bin/rpc-server $out/bin/llama-rpc-server";