address Windows windsys.c analyzer complaints

sys/windows/windsys.c(419): warning C6387: 'hMod' could be '0':
  this does not adhere to the specification for the function 'GetProcAddress'.

sys/windows/windsys.c(437): warning C28159:
  Consider using 'GetTickCount64' instead of 'GetTickCount'.
  Reason: GetTickCount overflows roughly every 49 days.  Code that does not
          take that into account can loop indefinitely.
          GetTickCount64 operates on 64 bit values and does not have that
          problem

sys/windows/windsys.c

@@ -416,12 +416,14 @@ static HWND
 GetConsoleHandle(void)
 {
     HMODULE hMod = GetModuleHandle("kernel32.dll");
-    GETCONSOLEWINDOW pfnGetConsoleWindow =
-        (GETCONSOLEWINDOW) GetProcAddress(hMod, "GetConsoleWindow");
-    if (pfnGetConsoleWindow)
-        return pfnGetConsoleWindow();
-    else
-        return GetConsoleHwnd();
+
+    if (hMod) {
+        GETCONSOLEWINDOW pfnGetConsoleWindow =
+            (GETCONSOLEWINDOW) GetProcAddress(hMod, "GetConsoleWindow");
+        if (pfnGetConsoleWindow)
+            return pfnGetConsoleWindow();
+    }
+    return GetConsoleHwnd();
 }
 
 static HWND
@@ -434,7 +436,7 @@ GetConsoleHwnd(void)
     /* Get current window title */
     GetConsoleTitle(OldTitle, sizeof OldTitle);
 
-    (void) sprintf(NewTitle, "NETHACK%ld/%ld", GetTickCount(),
+    (void) sprintf(NewTitle, "NETHACK%lld/%ld", GetTickCount64(),
                    GetCurrentProcessId());
     SetConsoleTitle(NewTitle);