+
+# Also add in libc++ and compiler-rt trees if present (and we have
+# a sufficiently recent version of CMake where required).
+if(${LLVM_BUILD_RUNTIME})
+ # MSVC isn't quite working with libc++ yet, disable it until issues are
+ # fixed.
+ if(NOT MSVC)
+ add_llvm_external_project(libcxx)
+ endif()
+ if(NOT LLVM_BUILD_EXTERNAL_COMPILER_RT)
+ add_llvm_external_project(compiler-rt)
+ endif()
+endif()
+
+add_llvm_external_project(dragonegg)