CMake: If we have `clang' under the `tools/' subdirectory, add it to
the build.

llvm-svn: 58179
diff --git a/llvm/tools/CMakeLists.txt b/llvm/tools/CMakeLists.txt
index 8909cbd..d05cb9a 100644
--- a/llvm/tools/CMakeLists.txt
+++ b/llvm/tools/CMakeLists.txt
@@ -30,3 +30,7 @@
 add_subdirectory(llvm-bcanalyzer)
 add_subdirectory(llvm-stub)
 add_subdirectory(llvmc2)
+
+if( EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/clang/CMakeLists.txt )
+  add_subdirectory( ${CMAKE_CURRENT_SOURCE_DIR}/clang )
+endif( EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/clang/CMakeLists.txt )