src: avoid unused variables and functions

PR-URL: nodejs#45542
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>

src/inspector_agent.cc

@@ -52,7 +52,9 @@ using v8_inspector::StringView;
 using v8_inspector::V8Inspector;
 using v8_inspector::V8InspectorClient;
 
+#ifdef __POSIX__
 static uv_sem_t start_io_thread_semaphore;
+#endif  // __POSIX__
 static uv_async_t start_io_thread_async;
 // This is just an additional check to make sure start_io_thread_async
 // is not accidentally re-used or used when uninitialized.

src/node_binding.cc

@@ -222,7 +222,7 @@ static bool libc_may_be_musl() {
   has_cached_retval = true;
   return retval;
 }
-#else  // __linux__
+#elif defined(__POSIX__)
 static bool libc_may_be_musl() { return false; }
 #endif  // __linux__
 

src/node_credentials.cc

@@ -456,12 +456,12 @@ static void Initialize(Local<Object> target,
                        Local<Value> unused,
                        Local<Context> context,
                        void* priv) {
-  Environment* env = Environment::GetCurrent(context);
-  Isolate* isolate = env->isolate();
-
   SetMethod(context, target, "safeGetenv", SafeGetenv);
 
 #ifdef NODE_IMPLEMENTS_POSIX_CREDENTIALS
+  Environment* env = Environment::GetCurrent(context);
+  Isolate* isolate = env->isolate();
+
   READONLY_TRUE_PROPERTY(target, "implementsPosixCredentials");
   SetMethodNoSideEffect(context, target, "getuid", GetUid);
   SetMethodNoSideEffect(context, target, "geteuid", GetEUid);