internal.h: add BITFIELD macro to aid C99 users

I plan to use this macro to pack other enums in the VM.

* internal.h: add BITFIELD macro
* method.h: use BITFIELD for rb_method_visibility_t
  [ruby-core:85074] [Misc #14395]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62077 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 7 deletions

diff --git a/method.h b/method.h
index 83f3acac06..e2d121d9b8 100644
--- a/method.h
+++ b/method.h
@@ -32,16 +32,10 @@ typedef enum {
     METHOD_VISI_MASK = 0x03
 } rb_method_visibility_t;
 
-#if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
-#define bits_t rb_method_visibility_t
-#else
-#define bits_t unsigned int
-#endif
 typedef struct rb_scope_visi_struct {
-    bits_t method_visi : 3;
+    BITFIELD(rb_method_visibility_t) method_visi : 3;
     unsigned int module_func : 1;
 } rb_scope_visibility_t;
-#undef bits_t
 
 /*! CREF (Class REFerence) */
 typedef struct rb_cref_struct {