Update README build instructions (#112)

Author: nenorbot

README.md

@@ -31,7 +31,7 @@ mkdir llvm-inst
 mkdir llvm-build
 cd llvm-build
 
-cmake -DLLVM_ENABLE_PROJECTS="clang;lldb;libcxx;libcxxabi" -DCMAKE_INSTALL_PREFIX=~/buildspace/llvm-inst/ -GNinja ../llvm-project/llvm
+cmake -DLLVM_ENABLE_PROJECTS="clang;lldb" -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi" -DCMAKE_INSTALL_PREFIX=~/buildspace/llvm-inst/ -GNinja ../llvm-project/llvm
 ninja
 ninja install