diff --git a/tests/libtest/lib3207.c b/tests/libtest/lib3207.c
index 040e802511..e3b50ff40f 100644
--- a/tests/libtest/lib3207.c
+++ b/tests/libtest/lib3207.c
@@ -71,7 +71,7 @@ static size_t write_memory_callback(char *contents, size_t size,
 #if defined(USE_THREADS_POSIX) || defined(USE_THREADS_WIN32)
 static CURL_THREAD_RETURN_T CURL_STDCALL test_thread(void *ptr)
 #else
-static void test_thread(void *ptr)
+static unsigned int test_thread(void *ptr)
 #endif
 {
   struct Ctx *ctx = (struct Ctx *)ptr;