Add posix headers to toynet.h, move xioctl() to lib.c, introduce lib/net.c and move xsocket() to it.
diff --git a/lib/lib.h b/lib/lib.h
index 18c0155..ab858f9 100644
--- a/lib/lib.h
+++ b/lib/lib.h
@@ -119,6 +119,8 @@
 off_t lskip(int fd, off_t offset);
 char *readfile(char *name);
 char *xreadfile(char *name);
+void msleep(long miliseconds);
+int xioctl(int fd, int request, void *data);
 char *xgetcwd(void);
 void xstat(char *path, struct stat *st);
 char *xabspath(char *path, int exact);
@@ -152,6 +154,9 @@
 void for_each_pid_with_name_in(char **names, int (*callback)(pid_t pid, char *name));
 unsigned long xstrtoul(const char *nptr, char **endptr, int base);
 
+// net.c
+int xsocket(int domain, int type, int protocol);
+
 // getmountlist.c
 struct mtab_list {
   struct mtab_list *next;