[m-rev.] for review: update README.MacOS

[Julien Fischer]

For review by Ian
-----------------

Update README.MacOS.

Update README.MacOS to cover version 10.9  (Xcode 5).

README.MacOS:
 	Add a contents section the top of this file.

 	Merge the sections covering Mac OS X 10.5 - 10.8 into one section that
 	also covers 10.9.

 	The source distribution will no longer be built in the none.gc grade.

 	Add separate sections discussing Xcode 4 and Xcode 5 specific issues.

         Mention that Homebrew and Fink are also a source of GCC packages for
    	Mac OS X (in addition to MacPorts).

 	Mac OS 10.3 was only supported on PowerPC machines, not as we seem
 	to suggest here also Intel machines.

Julien.

diff --git a/README.MacOS b/README.MacOS
index 13cbd5f..6d03a52 100644
--- a/README.MacOS
+++ b/README.MacOS
@@ -1,53 +1,53 @@
  This file documents the port of Mercury to Mac OS X,
  i.e. the "*-apple-darwin*" configuration.

-================================================================
-IMPORTANT NOTE FOR FOR USERS OF MAC OS X 10.7 AND 10.8 (XCODE 4)
-================================================================
-
-The default C compiler provided with XCode 4.* is llvm-gcc.
-Mercury does NOT work with llvm-gcc.  Note that with XCode 4.* the executable
-named "gcc" is actually a symbolic link for llvm-gcc.
-
-In order to build Mercury you will need to a C compiler other than llvm-gcc,
-for example clang (See README.clang for further details) or actual GCC.  Recent
-version of XCode no longer ship actual GCC, so if you wish to use that you will
-need to install it yourself.  (The MacPorts project,
-<http://www.macports.org/>, provides more recent versions of GCC for Mac OS X.)
-
-As llvm-gcc is no longer supported as of version 3.0 of LLVM, we have no
-intention of ever supporting Mercury with it.
-
-----------------------------------
-Mercury on Mac OS X 10.5 and 10.6
-----------------------------------
-
-Mercury should build and install "out-of-the-box" on Mac OS X 10.5 or 10.6
-using Apple's gcc version 4.2.  This version of gcc is included with the
-Developer Tools.  On Mac OS X 10.6 you may also use clang.
-
-The 'asm_fast*' and 'reg*' grades are not currently available on Mac OS X 10.5
-or 10.6.  The only low-level C grades available are the 'none*' grades.  The
-high-level C, Java, Erlang and C# grades all work.  The 'erlang' grade requires
-an Erlang installation to be available and the C# grades require the Mono .NET
+--------
+Contents
+--------
+
+* Mercury on Mac OS X 10.5 to 10.9
+* Note for users of Xcode 5
+* Note for users of Xcode 4
+* Mercury on Mac OS X 10.4 and 10.3
+* Mercury on older versions of Mac OS X
+* Deployment Target Settings
+* PowerPC Linking Problems
+* Known bugs and unsupported features
+* Deep profiling on Mac OS X
+
+--------------------------------
+Mercury on Mac OS X 10.5 to 10.9
+--------------------------------
+
+Mercury should build and install "out-of-the-box" on Intel Mac OS X systems
+from version 10.5 or later.  For information about installing Mercury on
+versions of Mac OS X before 10.5, including on PowerPC systems, see the
+sections below.
+
+The 'asm_fast*' and 'reg*' grades are not available on Intel Mac OS X systems.
+The only low-level C grades available are the 'none*' grades.  The high-level
+C, Java, Erlang and C# grades all work.  The 'erlang' grade requires an Erlang
+installation to be available and the C# grades require the Mono .NET
  implementation.  (See README.Erlang and README.CSharp for further details.)

-When installing from the source distribution the configure script will
-automatically select the 'none.gc' grade for building the Mercury system.
  Unless otherwise directed, the 'hlc.gc' grade will be used as the default grade
  for compiling applications.

  By default, 64-bit versions of the executables and libraries in the Mercury
-system will be installed on x86-64 machines running Mac OS X 10.6.  To build a
-32-bit installation on such a machine, you need to arrange to have the option
-"-m32" passed to gcc or clang.  This can be done by invoking Mercury's
+system will be installed on x86-64 machines running Mac OS X 10.6 or later.  To
+build a 32-bit installation on such a machine, you need to arrange to have the
+option "-m32" passed to clang or gcc.  This can be done by invoking Mercury's
  configure script with the option:

+    --with-cc="clang -m32"
+
+or:
+
      --with-cc="gcc -m32"

  By default, 32-bit versions of the executables and libraries are installed on
  x86-64 machines running Mac OS X 10.5.  To build and install 64-bit Mercury on
-such a system you must pass the "-m64" option to gcc. 
+such a system you must pass the "-m64" option to the C compiler.

  Note that if you are building Mercury from scratch using an existing installed
  Mercury compiler, i.e. you are not installing using the pre-generated C files in
@@ -70,12 +70,44 @@ If, after installing Mercury, you encounter errors about missing .mih files,
  and you have fink installed, then try removing the fink components from your
  PATH (these usually start with /sw) and reinstalling.

+
+-------------------------
+Note for users of Xcode 5
+-------------------------
+
+With Xcode 5.* the executable named "gcc" is actually just a synonym for clang.
+Mercury's configure script is aware of this and it should not cause any
+problems.  If you wish to use actual GCC instead of clang you will need to
+install GCC (see the following section for further information).
+
+
+-------------------------
+Note for users of Xcode 4
+-------------------------
+
+The default C compiler provided with XCode 4.* is llvm-gcc.
+Mercury does NOT work with llvm-gcc.  Note that with XCode 4.* the executable
+named "gcc" is actually a symbolic link for llvm-gcc.
+
+In order to build Mercury you will need to a C compiler other than llvm-gcc,
+for example clang (See README.clang for further details) or actual GCC.  Recent
+versions of XCode no longer ship actual GCC, so if you wish to use that you will
+need to install it yourself.  Mac OS X packages for GCC are provided by:
+
+   * The MacPorts project <http://www.macports.org/>
+   * Homebrew             <http://brew.sh>
+   * The Fink project     <http://www.finkproject.org>
+
+As llvm-gcc is no longer supported as of version 3.0 of LLVM, we have no
+intention of ever supporting Mercury with it.
+
+
  ---------------------------------
  Mercury on Mac OS X 10.3 and 10.4
  ---------------------------------

-Mercury should work on Mac OS X 10.3 and 10.4 (both PowerPC and Intel),
-although it has not been tested with either of these for some time.
+Mercury should work on Mac OS X 10.3 (PowerPC) and 10.4 (both PowerPC and
+Intel), although it has not been tested with either of these for some time.

  Apple gcc 2.95 does not work with Mercury because it cannot handle the length
  of some of the identifier names that the Mercury compiler generates.