diff --git a/macros/gr_pwin32.m4 b/macros/gr_pwin32.m4
index 6cae28347..090972f78 100644
--- a/macros/gr_pwin32.m4
+++ b/macros/gr_pwin32.m4
@@ -31,7 +31,7 @@ AC_CHECK_HEADERS([winioctl.h winbase.h], [], [], [
 	#endif
 ])
 
-AC_CHECK_FUNCS([getopt getopt_long usleep sleep gettimeofday])
+AC_CHECK_FUNCS([getopt getopt_long usleep sleep nanosleep gettimeofday])
 AC_CHECK_TYPES([struct timezone, ssize_t],[],[],[
      #if HAVE_SYS_TYPES_H
      # include <sys/types.h>
diff --git a/src/sleep.c b/src/sleep.c
index 29c058118..ee41a164d 100644
--- a/src/sleep.c
+++ b/src/sleep.c
@@ -35,6 +35,7 @@
  * \param same as man page for each
  *
  */
+#ifdef HAVE_NANOSLEEP
 #include <unistd.h>
 #include <errno.h>
 #include <time.h>
@@ -70,3 +71,4 @@ int usleep(useconds_t usec)
 
     return 0;
 }
+#endif // HAVE_NANOSLEEP