lineage: Isolate LineageOS versions properties for build.prop

 * Our properties were supposed to go to /system/etc/prop.default
    after the following commit:
    "lineage: Move to Google's method of defining system default props"
    Change-Id: I6cb0e28a7599b010b389cc541015a37010a00f4b

 * However if BOARD_PROPERTY_OVERRIDES_SPLIT_ENABLED is not true,
    only /default.prop will retain the properties contents of
    ADDITIONAL_DEFAULT_PROPERTIES and PRODUCT_SYSTEM_DEFAULT_PROPERTIES,
    and none of our versioning identification was held in the system

 * Enabling BOARD_PROPERTY_OVERRIDES_SPLIT_ENABLED globally would
    break all properties on devices that handle partitions usually
    at the device level rather than the kernel due to mounting races

 * Create a new main_version.mk file to isolate LineageOS properties
    that define the system's versions identifications, and use the
    ADDITIONAL_BUILD_PROPERTIES internal build variable to include
    from build/make through a common vendor main.mk entrypoint

Change-Id: I0060141c097b3d14c3710eee1e0caf7110634967
Signed-off-by: Adrian DC <radian.dc@gmail.com>
4 files changed