Merge up to 8597 to experimental/gc from the bleeding edge.

build/README.txt

 This directory contains the V8 GYP files used to generate actual project files
 for different build systems.
 
 This is currently work in progress but this is expected to replace the SCons
 based build system.
 
 To use this a checkout of GYP is needed inside this directory. From the root of
 the V8 project do the following:
 
 $ svn co http://gyp.googlecode.com/svn/trunk build/gyp
 
-To generate Makefiles and build 32-bit version on Linux:
---------------------------------------------------------
+Note for the command lines below that Debug is the default configuration,
+so specifying that on the command lines is not required.
 
-$ GYP_DEFINES=target_arch=ia32 build/gyp_v8
-$ make
 
-To generate Makefiles and build 64-bit version on Linux:
---------------------------------------------------------
+To generate Makefiles on Linux:
+-------------------------------
 
-$ GYP_DEFINES=target_arch=x64 build/gyp_v8
-$ make
+$ build/gyp_v8
 
-To generate Makefiles and build for the arm simulator on Linux:
----------------------------------------------------------------
+This will build makefiles for ia32, x64 and the ARM simulator with names
+Makefile-ia32, Makefile-x64 and Makefile-armu respectively.
 
-$ build/gyp_v8 -I build/arm.gypi
-$ make
+To build and run for ia32 in debug and release version do:
+
+$ make -f Makefile-ia32
+$ out/Debug/shell
+$ make -f Makefile-ia32 BUILDTYPE=Release
+$ out/Release/shell
+
+Change the makefile to build and run for the other architectures.
+
+
+To generate Xcode project files on Mac OS:
+------------------------------------------
+
+$ build/gyp_v8
+
+This will make an Xcode project for the ia32 architecture. To build and run do:
+
+$ xcodebuild -project build/all.xcodeproj
+$ samples/build/Debug/shell
+$ xcodebuild -project build/all.xcodeproj -configuration Release
+$ samples/build/Release/shell
+
 
 To generate Visual Studio solution and project files on Windows:
 ----------------------------------------------------------------
 
 On Windows an additional third party component is required. This is cygwin in
 the same version as is used by the Chromium project. This can be checked out
 from the Chromium repository. From the root of the V8 project do the following:
 
 > svn co http://src.chromium.org/svn/trunk/deps/third_party/cygwin@66844 third_party/cygwin
 
 To run GYP Python is required and it is reccomended to use the same version as
 is used by the Chromium project. This can also be checked out from the Chromium
 repository. From the root of the V8 project do the following:
 
 > svn co http://src.chromium.org/svn/trunk/tools/third_party/python_26@70627 third_party/python_26
 
-Now generate Visual Studio solution and project files:
+Now generate Visual Studio solution and project files for the ia32 architecture:
 
-> third_party\python_26\python build/gyp_v8 -D target_arch=ia32
+> third_party\python_26\python build/gyp_v8
 
 Now open build\All.sln in Visual Studio.