Added include protection for unistd.h and sys/time.h.

diff --git a/loader/task.c b/loader/task.c
index 6e5b247..6a1dfee 100644
--- a/loader/task.c
+++ b/loader/task.c
@@ -24,7 +24,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
-#include <unistd.h>
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>
+#endif
 
 #include "winbase.h"
 #include "wingdi.h"