test: Avoid a warning about a cast to a smaller integer type on 64 bit architectures

test/hello-tls.c

@@ -19,6 +19,7 @@
 #include <windows.h>
 #include <stdio.h>
 #include <process.h>
+#include <stdint.h>
 
 #if defined(_MSC_VER)
 static __declspec(thread) int tlsvar = 1;
@@ -27,7 +28,7 @@ static __thread int tlsvar = 1;
 #endif
 
 static unsigned __stdcall threadfunc(void* arg) {
-    int id = (int)arg;
+    int id = (int)(intptr_t)arg;
     printf("thread %d, tlsvar %p initially %d\n", id, &tlsvar, tlsvar);
     tlsvar = id + 100;
     for (int i = 0; i < 4; i++) {