Added missing definition of 'PRIu32' in some RIOT include files

to avoid a bug in mspgcc's standard library

core/include/queue.h

@@ -11,6 +11,12 @@
 
 #include <stdlib.h>
 #include <stdint.h>
+#include <inttypes.h>
+
+// mspgcc bug : PRIxxx macros not defined before mid-2011 versions
+#ifndef PRIu32
+#define PRIu32 "lu"
+#endif
 
 typedef struct queue_node_t {
     struct queue_node_t *next;

sys/include/timex.h

@@ -2,6 +2,12 @@
 #define __TIMEX_H
 
 #include <stdint.h>
+#include <inttypes.h>
+
+// mspgcc bug : PRIxxx macros not defined before mid-2011 versions
+#ifndef PRIu32
+#define PRIu32 "lu"
+#endif
 
 typedef struct timex_t {
     uint32_t seconds;