* Packaged libsparse
libsparse from the Android project provides multiple tools like img2simg
and simg2img.
These are used to split a large image for the system partition into
separate smaller chunks with sparse headers
This is required for several devices (at least bullhead, fp2 and titan)
because it fixes the "Invalid sparse file format at header magi" error
https://github.com/postmarketOS/pmbootstrap/issues/299
* Added new variable deviceinfo_flash_sparse (fixes#299)
Right after the system image is generated, pmbootstrap checks this
variable. In case it is true, run img2simg on it
* motorola-titan: enable deviceinfo_flash_sparse
* libsparse: use source from github: anestisb/android-simg2img
It is not that easy to use the upstream archive because everytime
you download it, the files have the current date as creation date
and that makes the file have a different checksum every download
https://github.com/postmarketOS/pmbootstrap/pull/303#issuecomment-319017197
