extconf.rb in sleepy_penguin-3.5.1

- old
+ new

@@ -32,6 +32,7 @@
 have_func('rb_thread_io_blocking_region')
 have_func('rb_thread_fd_close')
 have_func('rb_update_max_fd')
 have_func('rb_fd_fix_cloexec')
 have_func('rb_io_get_io')
+have_func('rb_struct_size')
 create_makefile('sleepy_penguin_ext')