Improve NDK version handling
Right now we only have the latest revision (a,b,c) of every NDK version (11,12,13,...) available on the buildserver. This is inconvenient because when we bump the NDK revision we need to manually adjust new versions of apps which reference this NDK version.
On the other hand we need to specify the exact NDK revision for reproducibility.
Adding all ndk versions/revisions to the buildserver will add to it's size and provisioning time a significant amount. This probably doesn't matter all that much for the production setup but is not very convenient for testing builds in a real server environment.
- Add all ndk revisions to the production server. The fdroidserver software should be fine with them all being present and used.
- Add a new config option for ndk entries in
config.py. Instead of specifying a path we can also specify
pull, which indicates that fdroid build will download, verify and install the ndk release before starting the build.
1. is actually optional but might be nice for the bandwidth use buildserver.
2. will significantly reduce the space requirement for having a buildserver-like environment setup.