take purely descriptor-related stuff from fcntl.c to file.c

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/file.h b/include/linux/file.h
index 86795ec..da84fa0 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -30,7 +30,9 @@
 extern struct file *fget_light(unsigned int fd, int *fput_needed);
 extern struct file *fget_raw(unsigned int fd);
 extern struct file *fget_raw_light(unsigned int fd, int *fput_needed);
+extern int f_dupfd(unsigned int from, struct file *file, unsigned flags);
 extern void set_close_on_exec(unsigned int fd, int flag);
+extern bool get_close_on_exec(unsigned int fd);
 extern void put_filp(struct file *);
 extern int alloc_fd(unsigned start, unsigned flags);
 extern int get_unused_fd_flags(unsigned flags);