build: fix compile problems pointed out by gcc 4.4

src/sim/eventq.hh

@@ -471,7 +471,7 @@ class EventWrapper : public Event
 inline void
 EventQueue::schedule(Event *event, Tick when)
 {
-    assert(when >= curTick);
+    assert((UTick)when >= (UTick)curTick);
     assert(!event->scheduled());
 #ifdef EVENTQ_DEBUG
     assert((event->flags & Event::Initialized) == Event::Initialized);

src/sim/process.cc

@@ -32,6 +32,8 @@
 
 #include <unistd.h>
 #include <fcntl.h>
+
+#include <cstdio>
 #include <string>
 
 #include "arch/remote_gdb.hh"

src/sim/syscall_emul.cc

@@ -32,8 +32,9 @@
 #include <fcntl.h>
 #include <unistd.h>
 
-#include <string>
+#include <cstdio>
 #include <iostream>
+#include <string>
 
 #include "sim/syscall_emul.hh"
 #include "base/chunk_generator.hh"