On my Debian System I installed the package pure data.
$ aptitude show puredata
will tell you that "This is a metapackage that depends on all components of the core of Pd". and corresponds to Pd vanilla, but is being broken up into several packages.
Don't tell your apt(itude) to install suggested packages automatically. This is why it wants to install externals which you don't need. It should only install packages that "puredata" depends on. Which these are can be seen with above command for example. None of these include externals apart from the ones included with vanilla. See the documentation of your package manager to diasable the "suggested" packages.