+#if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE)
+pid_t setpgrp(void);
+char *crypt(const char *, const char *);
+void encrypt(char *, int);
+void swab(const void *__restrict, void *__restrict, ssize_t);
+#endif
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE) \
+ || (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE+0 < 700)
+int usleep(unsigned);
+unsigned ualarm(unsigned, unsigned);
+#endif
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#define L_SET 0
+#define L_INCR 1
+#define L_XTND 2