barrier: fix missing include

src/common/barrier.c

@@ -15,7 +15,6 @@
  */
 
 #include <common/barrier.h>
-#include <pthread.h>
 
 int _starpu_barrier_init(_starpu_barrier_t *barrier, int count)
 {

src/common/barrier.h

@@ -21,6 +21,8 @@
 # define PTHREAD_BARRIER_SERIAL_THREAD -1
 #endif
 
+#include <pthread.h>
+
 typedef struct {
 	int count;
 	int reached;