With the -release flag, the script will perform a RelWithDebInfo build of LLVM, Clang, and Swift, and will also build a package of the release build if the build and tests succeed.
Swift SVN r4260
/usr/local/bin isn't on PATH in the Jenkins environment, so add a variable to point at cmake. Jenkins' "emulate clean checkout" behavior also clobbers clang when it's checked out inside an llvm checkout, so change the script to expect LLVM and Clang checked out side-by-side and create a symlink to Clang from the LLVM tree.
Swift SVN r3972
This script configures and builds LLVM, Clang, and Swift from a fresh checkout (which should be prepared by Jenkins) and then runs the Swift tests.
Swift SVN r3969
