Summary: Include headers for all std:: stuff used in the header + getpid().
```
#include <sys/types.h>
#include <unistd.h>
pid_t getpid(void);
pid_t getppid(void);
```
Reviewed By: @yfeldblum
Differential Revision:
D2535284
fb-gh-sync-id:
b1167e8f382878d27553161b9b569968006355b3
#pragma once
#include <fcntl.h>
+#include <sys/types.h>
#include <unistd.h>
+#include <algorithm>
+#include <deque>
+#include <iterator>
+#include <memory>
+#include <stdexcept>
+#include <utility>
+
#include <folly/io/async/EventBase.h>
#include <folly/io/async/EventHandler.h>
#include <folly/io/async/DelayedDestruction.h>
#include <folly/SpinLock.h>
#include <glog/logging.h>
-#include <deque>
#if __linux__ && !__ANDROID__
#define FOLLY_HAVE_EVENTFD