+
+/*
+ * Names of the interval timers, and structure
+ * defining a timer setting.
+ */
+#define ITIMER_REAL 0
+#define ITIMER_VIRTUAL 1
+#define ITIMER_PROF 2
+
+/*
+ * Select uses bit masks of file descriptors in longs. These macros
+ * manipulate such bit fields (the filesystem macros use chars). The
+ * extra protection here is to permit application redefinition above
+ * the default size.
+ */
+#ifndef FD_SETSIZE
+#define FD_SETSIZE __DARWIN_FD_SETSIZE
+#endif /* FD_SETSIZE */
+#ifndef FD_SET
+#define FD_SET(n, p) __DARWIN_FD_SET(n, p)
+#endif /* FD_SET */
+#ifndef FD_CLR
+#define FD_CLR(n,p) __DARWIN_FD_CLR(n, p)
+#endif /* FD_CLR */
+#ifndef FD_ISSET
+#define FD_ISSET(n, p) __DARWIN_FD_ISSET(n, p)
+#endif /* FD_ISSET */
+#ifndef FD_ZERO
+#define FD_ZERO(p) __DARWIN_FD_ZERO(p)
+#endif /* FD_ZERO */
+
+#if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
+
+#ifndef FD_COPY
+#define FD_COPY(f, t) __DARWIN_FD_COPY(f, t)
+#endif /* FD_COPY */