[PD-dev] Makefile.pdlibbuilder 0.0.0 on github

[katja]

After a few months of puzzling and testing it was time to push
Makefile.pdlibbuilder onto a public repository (before rumours would
become too embarrassing):

https://github.com/pure-data/pd-lib-builder

Makefile.pdlibbuilder is a one-size-fits-all helper makefile for Pd
external libraries. A build system in this approach will typically
have two makefiles:

1 - Makefile - defines input files and other library-dependent variables
2 - Makefile.pdlibbuilder - defines library-independent paths, flags
and build rules for Pd lib building

You can think of this approach as a template split in two parts -
specific and generic. Your Makefile is the specific part, to be
updated when you make changes in your library. Makefile.pdlibbuilder
is the generic part, to be updated in response to external conditions
like OS and hardware developments. This partitioning makes it easy to
(collectively) improve the generic part of the build system, and
upgrade by simple file replacement.

Makefile.pdlibbuilder is conceived in the same spirit as Hans
Christoph Steiner's Makefile Template, but differs from it in several
aspects (apart from the partitioning). It does not assume the strict
libdir layout as described in
https://puredata.info/docs/developer/Libdir. Source files (multiple)
and link flags may be defined per class. C and C++ are both supported.
For exact info read Makefile.pdlibbuilder's internal documentation
paragraphs.

The version number of this first public release is set at 0.0.0 to
express that Makefile.pdlibbuilder's life as a community project
starts here. It doesn't mean that this version is totally unstable. In
the course of testing with ~60 libraries on 7 platforms, the 'API' was
reconsidered a few times, but is now well defined. Discussions about
flags, default paths and priorities thereof are to be expected
however. Also, source packaging targets aren't implemented yet. And
hopefully there's an interest to add platform definitions, for cross
compiling in particular.

You may wonder why those ~60 library test makefiles (written by Fred
Jan Kraan) won't be published as such. Briefly: while it takes a few
minutes to write a library makefile for the Makefile.pdlibbuilder
approach, it takes a few hours or days to build and test a single
library on 7 platforms and make sure that the build result is
identical to that of the original build system. In some cases it is
hard to understand what the original build system means to build and
install, and there is a huge variety of build methods among
Pd-extended libs. Fred Jan's test makefiles mainly served to figure
out the requirements for Makefile.pdlibbuilder. We concluded that most
libraries could be accommodated, including the rather complex case of
cyclone. Libraries which need to check dependencies before building
are still better served by Autotools.

Katja