IssueTracker

aapt was recently changed to stick two data elements in AndroidManifest.xml as part of the build process: platformBuildVersionName and platformBuildVersionCode.  These create unnecessary differences between builds and make it much harder to reproduce a given APK binary from the source code.  Having reproducible builds means smaller updates and helps catch security issues that work like XCodeGhost.

For more info on why reproducible builds are important:
* https://source.android.com/devices/tech/ota/reduce_size.html
* https://reproducible-builds.org/

Some ideas for how to fix this:
* make aapt only insert platformBuildVersionCode, that's easily reproducible
* revert aapt to the old behavior and not insert platformBuildVersionName and platformBuildVersionCode
* store platformBuildVersionName and platformBuildVersionCode elsewhere, like a file in META-INF/, or in a header to META-INF/MANIFEST.MF.  To check reproducible builds, we are currently building an unsigned APK, then copying META-INF into it, then running `apksigner verify`.

Here is where this change originates:
* https://android.googlesource.com/platform/frameworks/base/+/ad2d07d%5E!/
* https://android.googlesource.com/platform/frameworks/base/+/5283fab%5E!/

To see a log of build differences when building APKs:
https://verification.f-droid.org/