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, 3 insertions, 2 deletions

diff --git a/template/prelude.c.tmpl b/template/prelude.c.tmpl
index b582e2ddd6..a8b53d05c9 100644
--- a/template/prelude.c.tmpl
+++ b/template/prelude.c.tmpl
@@ -87,10 +87,11 @@ Prelude.new(output, ARGV, vpath).instance_eval do
  sources: <%= @preludes.map {|n,*| prelude_base(n)}.join(', ') %><%=%>
 */
 %unless @preludes.empty?
-#include "ruby/ruby.h"
 #include "internal.h"
-#include "vm_core.h"
+#include "internal/warnings.h"
 #include "iseq.h"
+#include "ruby/ruby.h"
+#include "vm_core.h"
 
 % preludes = @preludes.values.sort
 % preludes.each {|i, prelude, lines, sub|