Libraries: Makefile should know what libraries are needed by the core code

[giuliomoro]

e.g.: when linking in default_libpd_render.o we also need the Scope library (and its dependencies). See here https://github.com/giuliomoro/Bela/commit/542ddca2ba8735463e47879e69a36b8d823a4373

[giuliomoro]

perhaps add a file Makefile.pd.inc (generated from the default_libpd_render.ii)to be included for Pd projects that don't have custom cpp files.