I have set up automatic builds direct from trunk/externals of SVN for all libraries that are based on the Library Template[1]. It runs the script trunk/externals/build-all-libdirs.sh whenever there is a new commit anywhere in trunk/externals/. Its currently building on debian-stable-amd64 debian-testing-amd64 macosx105-i386 macosx105-powerpc, and macosx106-x86_64. Hopefully I'll get some Windows builds up there too.
[1] https://puredata.info/docs/developer/LibraryTemplate/
.hc