Binary package “pd-lib-builder” in ubuntu focal

common build system for Pure Data externals

 Makefile based build-system for Pure Data external libraries, with the
 following characteristics:
  - defines build settings based on autodetected OS and architecture
  - defines rules to build Pd class- or lib executables from C or C++ sources
  - defines rules for libdir installation
  - defines convenience targets for developer and user
  - evaluates implicit dependencies for non-clean builds