Copying debug ramdisk files to /debug_ramdisk/*

In previous implementation, userdebug sepoilcy and property files are
loaded from the system.img. This CL changes this to:

  - first-stage init copies userdebug files from ramdisk to /debug_ramisk/*
  - second-stage init loads files from /debug_ramdisk/*.

Note: same as before, the above can only be triggered, if the device
is UNLOCKED

With this, we don't have to put userdebug related files into the USER
system.img.

Bug: 126493225
Test: boot device with a ramdisk with /force_debuggable, checks related
      files are loaded
Change-Id: I63f5f846e82ba78427062bf7615c26173878d8f3
diff --git a/init/Android.mk b/init/Android.mk
index 39af0e6..efa8d87 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -68,12 +68,14 @@
 # Set up the same mount points on the ramdisk that system-as-root contains.
 LOCAL_POST_INSTALL_CMD := mkdir -p \
     $(TARGET_RAMDISK_OUT)/apex \
+    $(TARGET_RAMDISK_OUT)/debug_ramdisk \
     $(TARGET_RAMDISK_OUT)/dev \
     $(TARGET_RAMDISK_OUT)/mnt \
     $(TARGET_RAMDISK_OUT)/proc \
     $(TARGET_RAMDISK_OUT)/sys \
 
 LOCAL_STATIC_LIBRARIES := \
+    libc++fs \
     libfs_avb \
     libfs_mgr \
     libfec \