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, 23 insertions, 10 deletions

diff --git a/error.c b/error.c
index 9557d8552b..f99cdb6784 100644
--- a/error.c
+++ b/error.c
@@ -9,27 +9,40 @@
 
 **********************************************************************/
 
-#include "ruby/encoding.h"
-#include "ruby/st.h"
-#include "internal.h"
-#include "ruby_assert.h"
-#include "vm_core.h"
-#include "builtin.h"
+#include "ruby/config.h"
 
-#include <stdio.h>
+#include <errno.h>
 #include <stdarg.h>
+#include <stdio.h>
+
 #ifdef HAVE_STDLIB_H
-#include <stdlib.h>
+# include <stdlib.h>
 #endif
-#include <errno.h>
+
 #ifdef HAVE_UNISTD_H
-#include <unistd.h>
+# include <unistd.h>
 #endif
 
 #if defined __APPLE__
 # include <AvailabilityMacros.h>
 #endif
 
+#include "internal.h"
+#include "internal/error.h"
+#include "internal/eval.h"
+#include "internal/io.h"
+#include "internal/load.h"
+#include "internal/object.h"
+#include "internal/symbol.h"
+#include "internal/thread.h"
+#include "internal/variable.h"
+#include "ruby/encoding.h"
+#include "ruby/st.h"
+#include "ruby_assert.h"
+#include "vm_core.h"
+
+#include "builtin.h"
+
 /*!
  * \defgroup exception Exception handlings
  * \{