Upgrade to PD 0.48

[tkirshboim]

This pull request updates pd-for-android to the current libpd master branch which is based on PD 0.48.

The NDK build was initially failing for the following reasons which this PR solves:

• Issues that are solved in the Android.mk file in libpd (see related tkirshboim/libpd@066f763 )
• PD now using system calls 'munlockall' and 'mlockall' in https://github.com/pure-data/pure-data/blob/master/src/s_inter.c. These calls are apparently not present when building for Android 16 and below and for that reason the minimum API level had to be raised to 17.

The changes to Android.mk in the libpd repo should be merged first and then this PR could be updated to use the original libpd repo (instead of my own fork).

Pinging also @nettoyeurny : Perhaps you have a suggestion how raising the API level to 17 could be avoided?..

[tkirshboim]

The Circle CI build is failing, however I think this is because I'm using my own fork for libpd.
Once libpd/libpd#183 is merged I could change this PR to use the original libpd repo.

[rpattabi]

min sdk from 9 to 17 may be the only contention with this PR. Could we at least get it to 16? Jelly Bean is still alive unfortunately.

[joebowbeer]

Regarding min version, building current master with NDK r15 emits a warning that our min version is effectively android-14:

:PdCore:buildNative
Android NDK: android-9 is unsupported. Using minimum supported version android-14.
Android NDK: WARNING: APP_PLATFORM android-14 is higher than android:minSdkVersion 1
in pd-for-android/PdCore/AndroidManifest.xml. NDK binaries will *not* be comptible with
devices older than android-14.

See https://android.googlesource.com/platform/ndk/+/master/docs/user/common_problems.md
for more information.

This change was introduced in NDK r15:

https://github.com/android-ndk/ndk/wiki/Changelog-r15

[tkirshboim]

I've updated this PR and it is now based on the latest pd-for-android and libpd master branches.

Regarding the issue of raising the minimum required Android SDK version from 14 to 17:
This is required if we build the current pure-data sources with NDK. As far as I understand the munlockall and mlockall functions were added to NDK from API level 17. This is visible when comparing NDK functions for API level 16 with NDK functions for API level 17.

As far as I understand, the options we have to avoid raising the min API level is to either:

• Build pd-for-android using CMake (I don't know if this can actually solve this issue, this is just a guess). Or:
• Suggest a change in the pure-data core source code.

I won't be able to explore these options, but if anyone else is interested please bring this up.

I'd like to add that Android versions 14-16 are currently under 3% of all active Android devices according to Google and that it will still be possible to support these versions with pd-for-android version 1.0.2.

pinging @joebowbeer for a second review and @nettoyeurny for any comments on the issue of raising the minimal Android API level.

[joebowbeer]

I'm still hoping we can keep minSdkVersion at 14

[joebowbeer]

Remove obsolete comment

[joebowbeer]

As per discussion below, ndk installation can be performed by sdk-manager?

https://discuss.circleci.com/t/licences-for-android-build-tools-not-accepted/17285/22

[tkirshboim]

Yes, but then I assume we'll get the latest NDK version, not a specific one.
Since NDK builds are often sensitive to the NDK version that is used, perhaps it's better to keep this as it is right now?

[joebowbeer]

With enough stars, perhaps CircleCI will provide this ready-made:

https://github.com/circleci/circleci-images/issues/73

[evabishchevich]

Does minSdk prevent this PR from being merged?

[tkirshboim]

@joebowbeer latest commit also closes #78

[tkirshboim]

Might also close #79 (needs to be tested)