[commit: ghc] wip/nfs-locking: Update README.md (53784f5)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : wip/nfs-locking
Link       : http://ghc.haskell.org/trac/ghc/changeset/53784f526f5ee88136966f5f9c8328459334436b/ghc

>---------------------------------------------------------------

commit 53784f526f5ee88136966f5f9c8328459334436b
Author: Moritz Angermann <moritz.angermann at gmail.com>
Date:   Thu Jan 7 21:37:46 2016 +0800

    Update README.md
    
    - Trying to unify Linux / OS X / Windows build steps.
    - Added note about `src/Settings/User.hs`.
    [skip ci]


>---------------------------------------------------------------

53784f526f5ee88136966f5f9c8328459334436b
 README.md | 30 ++++++++++++------------------
 1 file changed, 12 insertions(+), 18 deletions(-)

diff --git a/README.md b/README.md
index 9f9de91..6a89dc6 100644
--- a/README.md
+++ b/README.md
@@ -23,36 +23,30 @@ identical to those for the `make` build system. This means that you don't need
 to adjust anything if you are already familiar with building ghc using the `make`
 build system.
 
-### Linux / Mac OS X
+### Getting the source and configuring GHC
 
 ```bash
-git clone git://git.haskell.org/ghc
+git clone --recursive git://git.haskell.org/ghc.git
 cd ghc
-git submodule update --init
 git clone git://github.com/snowleopard/shaking-up-ghc shake-build
 ./boot
-./configure
+./configure                                # on linux / os x
+./configure --enable-tarballs-autodownload # on windows
 ```
 
-Now you have a couple of options:
-
-- `./shake-build/build.sh` to run the script directly. You'll need to have
-  `shake` installed globally.
-- `./shake-build/build.cabal.sh` to install the build system in a Cabal sandbox
-  and then run it.
+### Configuring the build process
 
+`ghc` uses `mk/build.mk` to configure the build process. `shaking-up-ghc`
+uses `src/Settings/User.hs` for build specification.
 
-
-### Windows
+### Building GHC using `shaking-up-ghc`
 
 ```bash
-git clone --recursive git://git.haskell.org/ghc.git
-cd ghc
-git clone git://github.com/snowleopard/shaking-up-ghc shake-build
-./boot
-./configure --enable-tarballs-autodownload
-shake-build/build.bat
+./shake-build/build.sh       # linux / os x: to run the script directly. You'll need to have `shake` installed globally.
+./shake-build/build.cabal.sh # linux / os x: OR to install the build system in a Cabal sandbox and then run it.
+shake-build/build.bat        # windows
 ```
+
 Also see the [Building GHC on Windows guide][ghc-windows-building-guide].
 
 ### Resetting the build