introduce struct `rb_native_thread`

`rb_thread_t` contained `native_thread_data_t` to represent
thread implementation dependent data. This patch separates
them and rename it `rb_native_thread` and point it from
`rb_thraed_t`.

Now, 1 Ruby thread (`rb_thread_t`) has 1 native thread (`rb_native_thread`).

1 files changed, 4 insertions, 1 deletions

diff --git a/thread_none.h b/thread_none.h
index 3956fbfe7f..89f64667f0 100644
--- a/thread_none.h
+++ b/thread_none.h
@@ -8,8 +8,11 @@
 // based implementation in vm.c
 #define RB_THREAD_LOCAL_SPECIFIER
 
-typedef struct native_thread_data_struct {} native_thread_data_t;
+struct rb_native_thread {
+    void *thread_id; // NULL
+};
 
+struct rb_thread_sched_item {};
 struct rb_thread_sched {};
 
 RUBY_EXTERN struct rb_execution_context_struct *ruby_current_ec;