[8.9" Kindle Fire HD Q&A, Help & Troubleshooting] monster1612:
I'm trying to port CM13 over to this awesome device, and I am having some trouble. The porting guide on the CM wiki says that a kernel binary should have been created when I run mkvendor.sh on a boot image (which I extracted from a recent CM nightly .zip). However, it has not. Here's the output I obtained from mkvendor.sh:

chris@chris-werewolf:~/android/system$ ./build/tools/device/mkvendor.sh amazon jem ~/Downloads/boot.img
Arguments: amazon jem /home/chris/Downloads/boot.img
Output will be in /home/chris/android/system/device/amazon/jem
unpackbootimg: error while loading shared libraries: libc++.so: cannot open shared object file: No such file or directory
gzip: ../boot.img-ramdisk.gz: No such file or directory
cpio: premature end of archive
cat: /tmp/chris/bootimg/boot.img-base: No such file or directory
cat: /tmp/chris/bootimg/boot.img-cmdline: No such file or directory
cat: /tmp/chris/bootimg/boot.img-pagesize: No such file or directory
cp: cannot stat ‘/tmp/chris/bootimg/boot.img-zImage’: No such file or directory
Creating initial git repository.
~/android/system/device/amazon/jem ~/android/system
Initialized empty Git repository in /home/chris/android/system/device/amazon/jem/.git/
[master (root-commit) cc6cf31] mkvendor.sh: Initial commit of jem
7 files changed, 93 insertions(+)
create mode 100644 AndroidBoard.mk
create mode 100644 AndroidProducts.mk
create mode 100644 BoardConfig.mk
create mode 100644 cm.mk
create mode 100644 device_jem.mk
create mode 100644 recovery.fstab
create mode 100644 system.prop
~/android/system
Done!
Use the following command to set up your build environment:
lunch cm_jem-eng
chris@chris-werewolf:~/android/system$

I initially had the 'unpackbootimg not found.' message when running mkvendor.sh, and the fix in the CM wiki's porting guide did not help, so I copied all the binaries in ~/android/system/out/host/linux-x86/bin to ~/bin as directed in this XDA developers post (and while that post addresses building ClockWorkMod specifically, I felt that the instructions also applied to CM building). After trying that, the 'unpackbootimg' message disappeared, and mkvendor.sh produced the output I included earlier.

Additionally, when I try to run lunch cm_jem-eng or lunch cm_jem-userdebug (after adding cm_jem-userdebug to the lunch menu), I get this output:

chris@chris-werewolf:~/android/system$ lunch cm_jem-userdebug
Trying dependencies-only mode on a non-existing device tree?

============================================
PLATFORM_VERSION_CODENAME=REL
PLATFORM_VERSION=6.0
CM_VERSION=13.0-20151203-UNOFFICIAL-jem
TARGET_PRODUCT=cm_jem
TARGET_BUILD_VARIANT=userdebug
TARGET_BUILD_TYPE=release
TARGET_BUILD_APPS=
TARGET_ARCH=arm
TARGET_ARCH_VARIANT=armv7-a-neon
TARGET_CPU_VARIANT=cortex-a7
TARGET_2ND_ARCH=
TARGET_2ND_ARCH_VARIANT=
TARGET_2ND_CPU_VARIANT=
HOST_ARCH=x86_64
HOST_OS=linux
HOST_OS_EXTRA=Linux-4.2.0-19-generic-x86_64-with-Ubuntu-15.10-wily
HOST_BUILD_TYPE=release
BUILD_ID=MDB08M
OUT_DIR=/home/chris/android/system/out
============================================

chris@chris-werewolf:~/android/system$

I'm not exactly sure what I'm doing wrong, and I think I might need to pull down the device-specific code for CM 12.1 from CM's GitHub. Any ideas?﻿ Thanks in advance. :)