I managed to build llvm and clang and now I am trying to create a ClangTool according to [clang docs](http://clang.llvm.org/docs/LibASTMatchersTutorial.html#step-1-create-a-clangtool). But I am getting the following error when I am trying to build it:

```
CMake Error at tools/clang/tools/loop-convert/CMakeLists.txt:6 (target_link_libraries):
  The keyword signature for target_link_libraries has already been used with 
  the target "loop-convert".  All uses of target_link_libraries with a target
  must be either all-keyword or all-plain.

  The uses of the keyword signature are here:

    * cmake/modules/LLVM-Config.cmake:105 (target_link_libraries)
    * cmake/modules/AddLLVM.cmake:771 (target_link_libraries)

```

My current CMakeLists.txt is:

```
set(LLVM_LINK_COMPONENTS support)

add_clang_executable(loop-convert
  LoopConvert.cpp
)

target_link_libraries(loop-convert
  clangTooling
  clangBasic
  clangASTMatchers
)

```