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, 7 insertions, 2 deletions

diff --git a/proc.c b/proc.c
index e7178bebf5..cb5ffdab9a 100644
--- a/proc.c
+++ b/proc.c
@@ -10,10 +10,15 @@
 **********************************************************************/
 
 #include "eval_intern.h"
-#include "internal.h"
 #include "gc.h"
-#include "vm_core.h"
+#include "internal.h"
+#include "internal/class.h"
+#include "internal/error.h"
+#include "internal/object.h"
+#include "internal/proc.h"
+#include "internal/symbol.h"
 #include "iseq.h"
+#include "vm_core.h"
 
 /* Proc.new with no block will raise an exception in the future
  * versions */