kivy
build: add --android-target-sdk-version arg (defaults to android_api)
Currently p4a has a variable named android_api (set by e.g. buildozer via the app.android.api config key). In AndroidManifest.xml, both compileSdkVersion and targetSdkVersion are set to android_api.
This PR allows setting the targetSdkVersion and compileSdkVersion independently, by adding a --android-target-sdk-version build arg.
compileSdkVersion is a compilation setting used by e.g. the NDK at build-time, while targetSdkVersion is just a field to set in the manifest, only used at runtime (mainly in the Java world). (see e.g. https://stackoverflow.com/a/26694276 )
note: my current use case is to set targetSdkVersion to higher than compileSdkVersion, as I am using an older NDK (r22b) that only supports compileSdkVersion<=30, but the google play store now requires targetSdkVersion>=31. Historically it has sometimes been the case that p4a was using an old NDK, and I had to use this trick once already a few years ago, for the same reason (but atm p4a is using a very new NDK, I am just having troubles rebasing my fork). Regardless, I believe setting the two parameters independently might have other use cases.
I have a corresponding patch for buildozer to allow setting this in buildozer.spec, but will wait for feedback here first.
