The EROFS is planned to replace the ext4 as the file system format
of readonly partitions. This patch is enabling the ability to
build GSI with EROFS. The usage is
$ GSI_FILE_SYSTEM_TYPE=erofs make -j
Bug: 227552340
Test: lunch gsi_arm64-user; GSI_FILE_SYSTEM_TYPE=erofs make -j
Test: Verify the file system format of system.img
Change-Id: Ie815002c677d099c4db0ab7ca22db16ac6123659
0c791bedb4