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, 12 deletions

diff --git a/thread.c b/thread.c
index da36b62f8b..73d60b0fe3 100644
--- a/thread.c
+++ b/thread.c
@@ -64,23 +64,34 @@
 /* for model 2 */
 
 #include "ruby/config.h"
-#include "ruby/io.h"
+
+#ifdef __linux__
+// Normally,  gcc(1)  translates  calls to alloca() with inlined code.  This is not done when either the -ansi, -std=c89, -std=c99, or the -std=c11 option is given and the header <alloca.h> is not included.
+# include <alloca.h>
+#endif
+
 #include "eval_intern.h"
-#include "timev.h"
-#include "ruby/thread.h"
-#include "ruby/thread_native.h"
-#include "ruby/debug.h"
 #include "gc.h"
+#include "hrtime.h"
 #include "internal.h"
+#include "internal/class.h"
+#include "internal/error.h"
+#include "internal/hash.h"
+#include "internal/io.h"
+#include "internal/object.h"
+#include "internal/proc.h"
+#include "internal/signal.h"
+#include "internal/thread.h"
+#include "internal/time.h"
+#include "internal/warnings.h"
 #include "iseq.h"
-#include "vm_core.h"
 #include "mjit.h"
-#include "hrtime.h"
-
-#ifdef __linux__
-// Normally,  gcc(1)  translates  calls to alloca() with inlined code.  This is not done when either the -ansi, -std=c89, -std=c99, or the -std=c11 option is given and the header <alloca.h> is not included.
-#include <alloca.h>
-#endif
+#include "ruby/debug.h"
+#include "ruby/io.h"
+#include "ruby/thread.h"
+#include "ruby/thread_native.h"
+#include "timev.h"
+#include "vm_core.h"
 
 #ifndef USE_NATIVE_THREAD_PRIORITY
 #define USE_NATIVE_THREAD_PRIORITY 0