Originally Posted by Fyren
Off the top of my head, you need to get the ambuild repo and then place the files where Python can find them. Then you run bootstrap.pl and startbuild.pl. These files may have hardcoded paths for compiler/Python binary names you'd have to change since they're intended for use by our specific build system.
Fyren is speaking ducks.
hg clone http://hg.alliedmods.net/ambuild/
python3 setup.py build
python3 setup.py install
hg clone http://hg.alliedmods.net/hl2sdks/hl2sdk-ob-valve/
hg clone http://hg.alliedmods.net/releases/mmsource-1.8/
hg clone http://hg.alliedmods.net/releases/sourcemod-1.4/
You should literally be able to paste that into a shell and download and compile SourceMod 1.4.