Add support for building vendor_ramdisk.img

Allow BoardConfig.mk to set:
BOARD_BUILD_VENDOR_RAMDISK_IMAGE := true

to build:
out/target/product/<name>/vendor_ramdisk.img

This is done to support GKI device kernel development.

Kernel developers build vmlinux + DTB + GKI kernel modules locally
and then use kernel build tools to output:

* vmlinux + ramdisk.img => boot.img
* GKI kernel modules + DTB + vendor_ramdisk.img => vendor_boot.img

In other words, kernel developers use ramdisk.img and vendor_ramdisk.img
as prebuilts for building flashable boot.img and vendor_boot.img
directly from the kernel development environment.

Test: make vendorramdisk with BOARD_BUILD_VENDOR_RAMDISK_IMAGE := true
Test: make vendorramdisk with BOARD_BUILD_VENDOR_RAMDISK_IMAGE omitted
Change-Id: Id67839887b6bf608f4a5f13384c551c12ee9fdbd
2 files changed
tree: 3810fdf71025d20b964ac6c1199fd0ca1637f94d
  1. common/
  2. core/
  3. packaging/
  4. target/
  5. tests/
  6. tools/
  7. .gitignore
  8. Android.bp
  9. buildspec.mk.default
  10. Changes.md
  11. CleanSpec.mk
  12. Deprecation.md
  13. envsetup.sh
  14. help.sh
  15. METADATA
  16. navbar.md
  17. OWNERS
  18. PREUPLOAD.cfg
  19. rbesetup.sh
  20. README.md
  21. tapasHelp.sh
  22. Usage.txt
README.md

Android Make Build System

This is the Makefile-based portion of the Android Build System.

For documentation on how to run a build, see Usage.txt

For a list of behavioral changes useful for Android.mk writers see Changes.md

For an outdated reference on Android.mk files, see build-system.html. Our Android.mk files look similar, but are entirely different from the Android.mk files used by the NDK build system. When searching for documentation elsewhere, ensure that it is for the platform build system -- most are not.

This Makefile-based system is in the process of being replaced with Soong, a new build system written in Go. During the transition, all of these makefiles are read by Kati, and generate a ninja file instead of being executed directly. That's combined with a ninja file read by Soong so that the build graph of the two systems can be combined and run as one.