git clone --recursive https://github.com/srcdslab/sm-ext-SMjansson

git clone https://github.com/alliedmodders/hl2sdk-manifests

vim hl2sdk-manifests/manifests/css.json
remove -Wno-nontrivial-memcall

rm -r -f build; mkdir build; cd build; python ../sm-ext-common/configure.py --ext-root=.. --sdks css --enable-optimize; ambuild; cd ..