unix/modtime: Unbreak Windows build after changes to check select() result.

unix/modtime.c

@@ -36,8 +36,9 @@
 #include "py/mphal.h"
 
 #ifdef _WIN32
-void msec_sleep_tv(struct timeval *tv) {
+static inline int msec_sleep_tv(struct timeval *tv) {
     msec_sleep(tv->tv_sec * 1000.0 + tv->tv_usec / 1000.0);
+    return 0;
 }
 #define sleep_select(a,b,c,d,e) msec_sleep_tv((e))
 #else