[CastXML] Build with an LLVM different from the installed version

[Brad King]

On 05/09/2017 01:29 AM, HSK wrote:
> [root at algenib CastXML]# CC=clang CXX=clang++ LLVM_DIR=/root/llvm-3.9.0.build cmake ./src

Make sure you have the LLVM/Clang build installed, e.g. via "make install".

Then run CMake with

```
$ mkdir build
$ cd build
$ CC=clang CXX=clang++ cmake /path/to/castxml -DLLVM_DIR=/root/llvm-3.9.0.install/lib/cmake/llvm
```

Note that the `src/` subdirectory within the castxml source tree should not
be given to CMake.  The top-level directory should be given.

-Brad