Updates on midi and build system

[Ant1r]

This PR is the raw state of my work. Its history could be way cleaner, but I can only submit as is for now.
It includes:

• many updates on the build system and afferent fixes
• commits from my recent PRs, mainly the Midi updates and other fixes
• the modernization of native code management

The latter allows to fix the CI build, as well as long standing issues about adding native code externals to Pd in Android apps.
Here is a quick description of the changes:

• PdCore now exports "prefab" directory with headers and libs, so externals can compile and link to libpd.
• apps that include externals (ScenePlayer and PdTest) are now built using the pd-core prefab.
• for this to work, it has been necessary to split PdCore as a separate library, and to "includeBuild" it, making pd-for-android a so-called Composite project.
  This has the benefit that now, pd-core dependency is declared by the apps the same as if they were standalone; so they can safely be taken as examples.

[joebowbeer]

Thanks for fixing the build!

Should the action runner be pinned to ubuntu-24.04 to match the selected ndkVersion?

Have compatibility requirements changed? If so, can you list the changes?

Any reductions in diffs (e.g. revert gratuitous changes) would be appreciated.

[Ant1r]

Have compatibility requirements changed? If so, can you list the changes?

mainly:
AGP 8.11.0
gradle 8.13
buildToolsVersion 35.0.0
ndk 27.2.12479018

Any reductions in diffs (e.g. revert gratuitous changes) would be appreciated

I'd love it!
But sorry, I can't do it now (until probably a few weeks).

[joebowbeer]

Regarding compatibility, I am asking about which devices (android version?) this pd-for-android is compatible with. Are some previously supported devices no longer supported? In other words, has the minimum supported android version changed?

I commented on the buildToolsVersion, which is apparently no longer needed:

https://github.com/libpd/pd-for-android/pull/150/files#r2203627128

[Ant1r]

android version

@tkirshboim had to bump minimum version from 17 to 28 (which is a huge jump!) two years ago when updating libpd. I think this is because of the glob() function only there since sdk28!
No change since then.

[Ant1r]

reductions in diffs

finally I could find the time.
this PR is replaced by the shorter #152 .