Building WebKit requires a WebKit source tree and Xcode version 2.3 or greater.
Type this command to build WebKit:
WebKit/WebKitTools/Scripts/build-webkit
Use the --debug option for a debug build, which includes debugging symbols and assertions:
WebKit/WebKitTools/Scripts/build-webkit --debug
By default, build-webkit places build products in WebKit/WebKitBuild. If your Xcode preferences specify a custom build products location, build-webkit places build products there.
More information about building WebKit is available on the WebKit Wiki.
To set a default build configuration for build-webkit and other scripts, use the set-webkit-configuration script:
WebKit/WebKitTools/Scripts/set-webkit-configuration --debug
WebKit/WebKitTools/Scripts/set-webkit-configuration --release
It's handy to put WebKit/WebKitTools/Scripts in your shell path so you can type commands like build-webkit without specifying a full path.