decouple internal.h headers

Saves comitters' daily life by avoid #include-ing everything from
internal.h to make each file do so instead.  This would significantly
speed up incremental builds.

We take the following inclusion order in this changeset:

1.  "ruby/config.h", where _GNU_SOURCE is defined (must be the very
    first thing among everything).
2.  RUBY_EXTCONF_H if any.
3.  Standard C headers, sorted alphabetically.
4.  Other system headers, maybe guarded by #ifdef
5.  Everything else, sorted alphabetically.

Exceptions are those win32-related headers, which tend not be self-
containing (headers have inclusion order dependencies).

1 files changed, 10 insertions, 4 deletions

diff --git a/enum.c b/enum.c
index cc77964ff9..867eec8f81 100644
--- a/enum.c
+++ b/enum.c
@@ -9,14 +9,20 @@
 
 **********************************************************************/
 
-#include "ruby/encoding.h"
+#include "id.h"
 #include "internal.h"
+#include "internal/compar.h"
+#include "internal/enum.h"
+#include "internal/hash.h"
+#include "internal/imemo.h"
+#include "internal/numeric.h"
+#include "internal/object.h"
+#include "internal/proc.h"
+#include "internal/rational.h"
 #include "ruby/util.h"
-#include "id.h"
+#include "ruby_assert.h"
 #include "symbol.h"
 
-#include <assert.h>
-
 VALUE rb_mEnumerable;
 
 static ID id_next;