Enable usleep under win32

win32/build/config.w32

@@ -219,6 +219,8 @@ ARG_ENABLE("memory-limit", "Enable memory limit checking code", "no");
 
 AC_DEFINE('MEMORY_LIMIT', PHP_MEMORY_LIMIT == "yes" ? 1 : 0);
 
+AC_DEFINE('HAVE_USLEEP', 1);
+
 /* For snapshot builders, where can we find the additional
  * files that make up the snapshot template? */
 ARG_WITH("snapshot-template", "Path to snapshot builder template dir", "no");