* We may use a custom offset to:
a) preserve data that oem wrote to the first bytes of misc
b) skip recovery flags written by the bootloader (e.g. --wipe_data)
For case a) one should set the offset 'x' to be at least greater than
the size of bootloader_message struct (2048 bytes). If this is the case,
then we zero out bytes x ~ x + 2047
For case b) one should set the offset to be strictly smaller than
the size of bootloader_message struct. If this is the case, then we
zero out bytes 0 ~ 2047.
This allows to clear any additional flag set by the bootloader,
that would otherwise be forgotten in misc.
This also guarantees that we do not involountarily wipe any data that
the oem may have written starting at byte 2048 (coff coff LG)
Change-Id: I2d4e0702a2d8cbbef6274a87ce9499b0f69310dd
* bootloader_message.cpp is the only file using
BOOTLOADER_MESSAGE_OFFSET_IN_MISC and WIPE_PACKAGE_OFFSET_IN_MISC,
so we can move their definitions to the cpp.
This prevents the need to set BOARD_RECOVERY_BLDRMSG_OFFSET
in every module that includes the header.
* Global cflags are no longer supported Oreo and up,
so set the BOARD_RECOVERY_BLDRMSG_OFFSET via make variable
* Simplify logic, always set BOARD_RECOVERY_BLDRMSG_OFFSET.
Change-Id: I2b902bcce7f5ca13472e0ac30ac01b4991294dbe
