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, 11 insertions, 3 deletions

diff --git a/pack.c b/pack.c
index ae5a9a18e2..8ba492fd3b 100644
--- a/pack.c
+++ b/pack.c
@@ -9,12 +9,20 @@
 
 **********************************************************************/
 
-#include "ruby/encoding.h"
-#include "internal.h"
-#include <sys/types.h>
+#include "ruby/config.h"
+
 #include <ctype.h>
 #include <errno.h>
 #include <float.h>
+#include <sys/types.h>
+
+#include "internal.h"
+#include "internal/bits.h"
+#include "internal/string.h"
+#include "internal/symbol.h"
+#include "internal/util.h"
+#include "internal/variable.h"
+
 #include "builtin.h"
 
 /*