Linux build fixes

examples/rt/rt.cpp

@@ -42,6 +42,7 @@
 #include <math.h>
 #include <algorithm>
 #include <assert.h>
+#include <string.h>
 #include <sys/types.h>
 #include "../timing.h"
 #include "../cpuid.h"

examples/tasks_pthreads.cpp

@@ -181,7 +181,7 @@ ISPCLaunch(void *f, void *d) {
 
 static void *
 lTaskEntry(void *arg) {
-    int threadIndex = (int)arg;
+    int threadIndex = (int)((int64_t)arg);
     int threadCount = nThreads;
     TaskFuncType func;