Reorganisation of the source tree

Most of the other users of the fptools build system have migrated to
Cabal, and with the move to darcs we can now flatten the source tree
without losing history, so here goes.

The main change is that the ghc/ subdir is gone, and most of what it
contained is now at the top level.  The build system now makes no
pretense at being multi-project, it is just the GHC build system.

No doubt this will break many things, and there will be a period of
instability while we fix the dependencies.  A straightforward build
should work, but I haven't yet fixed binary/source distributions.
Changes to the Building Guide will follow, too.

1 files changed, 114 insertions, 0 deletions

diff --git a/includes/README b/includes/README
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index 0000000000..aae99bf20b
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+++ b/includes/README
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+-----------------------------------------------------------------------------
+The External API to the GHC Runtime System.
+-----------------------------------------------------------------------------
+
+The header files in this directory form the external API for the
+runtime.  The header files are used in the following scenarios:
+
+  1. Included into the RTS source code itself.
+	In this case we include "Rts.h", which includes everything
+	else in the appropriate order.
+
+	Pretty much everything falls into this category.
+
+  2. Included into a .hc file generated by the compiler.
+	In this case we include Stg.h, which includes a
+	subset of the headers, in the appropriate order and
+	with the appropriate settings (e.g. global register variables
+	turned on).
+
+	Includes everything below Stg.h in the hierarchy (see below).
+
+  3. Included into external C source code.
+	The following headers are designed to be included into
+        external C  code (i.e. C code compiled using a GHC installation,
+        not part of GHC itself or the RTS):
+
+		HsFFI.h
+		RtsAPI.h
+		SchedAPI.h
+		RtsFlags.h
+		Linker.h
+
+	These interfaces are intended to be relatively stable.
+
+	Also Rts.h can be included to get hold of everything else, including
+	definitions of heap objects, info tables, the storage manager interface
+	and so on.  But be warned: none of this is guaranteed to remain stable
+	from one GHC release to the next.
+
+  4. Included into non-C source code, including Haskell (GHC itself)
+     and C-- code in the RTS.
+
+	The following headers are #included into non-C source, so
+	cannot contain any C code or declarations:
+		config.h
+		RtsConfig.h
+		Constants.h
+		DerivedConstants.h
+		ClosureTypes.h
+		StgFun.h
+		MachRegs.h
+		Liveness.h
+		StgLdvProf.h
+
+Here is a rough hierarchy of the header files by dependency.
+
+Rts.h
+  Stg.h
+    ghcconfig.h		/* configuration info derived by the configure script. */
+    RtsConfig.h		/* settings for Rts things (eg. eager vs. lazy BH) */
+    MachDeps.h		/* sizes of various basic types */
+    StgTypes.h		/* basic types specific to the virtual machine */
+    TailCalls.h		/* tail calls in .hc code */
+    StgDLL.h		/* stuff related to Windows DLLs */
+    MachRegs.h		/* global register assignments for this arch */
+    Regs.h		/* "registers" in the virtual machine */
+    StgProf.h		/* profiling gubbins */
+    StgMiscClosures.h	/* decls for closures & info tables in the RTS */
+    RtsExternal.h	/* decls for RTS things required by .hc code */
+      (RtsAPI.h)
+      (HsFFI.h)
+
+  RtsTypes.h		/* types used in the RTS */
+
+  Constants.h		/* build-time constants */
+  StgLdvProf.h
+  StgFun.h
+  Closures.h
+  Liveness.h		/* macros for constructing RET_DYN liveness masks */
+  ClosureMacros.h
+  ClosureTypes.h
+  InfoTables.h
+  TSO.h
+  Updates.h		/* macros for performing updates */
+  GranSim.h
+  Parallel.h
+  SMP.h
+  Block.h
+  StgTicky.h
+  Stable.h
+  Hooks.h
+  Signals.h
+  DNInvoke.h
+    Dotnet.h
+
+Cmm.h			/* included into .cmm source only */
+  DerivedConstants.h	/* generated by mkDerivedConstants.c from other */
+			/* .h files. */
+  (Constants.h)
+  (ClosureTypes.h)
+  (StgFun.h)
+  (MachRegs.h)
+  (Liveness.h)  
+  (Block.h)
+
+Bytecodes.h	/* Bytecode definitions for the interpreter */
+Linker.h	/* External API to the linker */
+RtsFlags.h	/* External API to the RTS runtime flags */
+SchedAPI.h	/* External API to the RTS scheduler */
+ieee-flpt.h	/* ToDo: needed? */
+
+RtsAPI.h	/* The top-level interface to the RTS (rts_evalIO(), etc.) */
+HsFFI.h		/* The external FFI api */
+