add missing include for pthread functions

tests/datawizard/dsm_stress.c

@@ -19,6 +19,7 @@
 #include <errno.h>
 #include <starpu.h>
 #include <stdlib.h>
+#include <pthread.h>
 
 #define N	10000
 

tests/datawizard/sync_with_data_with_mem_non_blocking.c

@@ -19,6 +19,7 @@
 #include <errno.h>
 #include <starpu.h>
 #include <stdlib.h>
+#include <pthread.h>
 
 #define NBUFFERS	64
 #define NITER		128

tests/microbenchs/prefetch_data_on_node.c

@@ -19,6 +19,7 @@
 #include <errno.h>
 #include <starpu.h>
 #include <stdlib.h>
+#include <pthread.h>
 
 #define N	1000
 

tests/overlap/overlap.c

@@ -19,6 +19,7 @@
 #include <errno.h>
 #include <starpu.h>
 #include <stdlib.h>
+#include <pthread.h>
 
 #define NTASKS	10000
 #define VECTORSIZE	1024