simgrid: Avoid including xbt/synchro.h when we have the s4u equivalent

include/starpu_thread.h

@@ -25,7 +25,10 @@
 #include <starpu_util.h>
 #ifdef STARPU_SIMGRID
 #include <pthread.h>
-#ifdef STARPU_HAVE_XBT_SYNCHRO_H
+#ifdef STARPU_HAVE_SIMGRID_MUTEX_H
+#include <simgrid/mutex.h>
+#include <simgrid/cond.h>
+#elif defined(STARPU_HAVE_XBT_SYNCHRO_H)
 #include <xbt/synchro.h>
 #else
 #include <xbt/synchro_core.h>