PATCH: Adds functions to run standalone tools and to parse the command line arguments from a compile command line database as generated by CMake

This is the next step in building the standalone tools infrastructure:
This patch simplifies writing of standalone Clang tools. As an
example, we add clang-check, a tool that runs a syntax only frontend
action over a .cc file. When you integrate this into your favorite
editor, you get much faster feedback on your compilation errors, thus
reducing your feedback cycle especially when writing new code.

The tool depends on integration of an outstanding patch to CMake to
work (cc'ed Brad King) which allows you to always have a current
compile command database in your cmake output directory when you set
CMAKE_EXPORT_COMPILE_COMMANDS.

The change has been reviewed by Zhanyong (and to a lesser extend by Chandler).

0001-Adds-functions-to-run-standalone-tools-and-to-parse-.patch (37.9 KB)