app : enable self-update only when built with llama-install.sh (#24754)

Signed-off-by: Adrien Gallouët <angt@huggingface.co>

app/llama.cpp

@@ -20,16 +20,21 @@ int llama_fit_params(int argc, char ** argv);
 int llama_quantize(int argc, char ** argv);
 int llama_perplexity(int argc, char ** argv);
 
-// hands the update over to the install script, which downloads and swaps the binary
+// Self-update is only supported for binaries built with llama-install.sh
 static int llama_update(int argc, char ** argv) {
     (void) argc;
     (void) argv;
 
+#ifdef LLAMA_INSTALL_BUILD
 #if defined(_WIN32)
     return system("powershell -NoProfile -ExecutionPolicy Bypass -Command \"irm https://llama.app/install.ps1 | iex\"");
 #else
     return system("curl -fsSL https://llama.app/install.sh | sh");
 #endif
+#else
+    printf("Updates are available only when installed from https://llama.app\n");
+    return 1;
+#endif
 }
 
 static const char * progname;
@@ -46,10 +51,16 @@ struct command {
     int (*func)(int, char **);
 };
 
+#ifdef LLAMA_INSTALL_BUILD
+#define UPDATE_HIDDEN false
+#else
+#define UPDATE_HIDDEN true
+#endif
+
 static const command cmds[] = {
     {"serve",         "HTTP API server",                                    {"server"},   false,         llama_server       },
     {"cli",           "Command-line interactive interface",                 {"client"},   false,         llama_cli          },
-    {"update",        "Update llama to the latest release",                 {},           false, llama_update       },
+    {"update",        "Update llama to the latest release",                 {},           UPDATE_HIDDEN, llama_update       },
     {"completion",    "Text completion",                                    {"complete"}, true,          llama_completion   },
     {"bench",         "Benchmark prompt processing and text generation",    {},           true,          llama_bench        },
     {"batched-bench", "Benchmark batched decoding performance",             {},           true,          llama_batched_bench},
@@ -61,6 +72,8 @@ static const command cmds[] = {
     {"help",          "Show available commands",                            {},           false,         help               },
 };
 
+#undef UPDATE_HIDDEN
+
 static int version(int argc, char ** argv) {
     printf("%s\n", llama_build_info());
     return 0;