[compat] improve thread naming logic

Signed-off-by: lizzie <lizzie@eden-emu.dev>

src/common/thread.cpp

@@ -109,7 +109,7 @@ void SetCurrentThreadName(const char* name) {
         // attempt to set a longer name with ERANGE.
         char buf[16];
         size_t const len = std::min<size_t>(std::strlen(name), sizeof(buf) - 1);
-        std::memcpy(truncated, name, len);
+        std::memcpy(buf, name, len);
         buf[len] = '\0';
         pthread_setname_np(pthread_self(), buf);
     }