It seems llvm headers are not in the include path even though I provide the -DLLVM_DIR path to LLVM config i.e /lib/cmake/llvm
Are there other options I need to provide to enable llvm include headers are correctly sourced ?
When I run ninja all, I get errors like
glow/include/glow/Graph/PlaceholderBindings.h:44:36: error: no template named 'StringMap' in namespace 'llvm'
  using PlaceholderNameMap = llvm::StringMap<Placeholder *>;

I had ran cmake as follows
cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug …/glow -DLLVM_DIR=<path/to/llvm>/local/lib/cmake/llvm