Compiling android - trying to add XML files to /system/etc/permissions - Android Q&A, Help & Troubleshooting

I'm compiling android from source. I've set up the environment, and tested the builds. Everything works fine.
My current objective is to add 10 custom xml files to /system/etc/permissions. I've tried modifying the Android.mk file in frameworks/base/data/etc to include the files, but the additions aren't appearing in the compiled system. What's strange is that the default files that were in the same folder and already in the makefile appear, so the makefile seems to be read and parsed at compile.
This is the code I'm using:
Code:
LOCAL_PATH := $(my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := [B]default_file_already_present.xml[/B]
LOCAL_MODULE_CLASS := ETC
LOCAL_MODULE_PATH := $(TARGET_OUT)/permissions
LOCAL_SRC_FILES := $(LOCAL_MODULE)
include $(BUILD_PREBUILT)
include $(CLEAR_VARS)
LOCAL_MODULE := [B]my_custom_file.xml[/B]
LOCAL_MODULE_CLASS := ETC
LOCAL_MODULE_PATH := $(TARGET_OUT)/permissions
LOCAL_SRC_FILES := $(LOCAL_MODULE)
include $(BUILD_PREBUILT)
For some reason, my_custom_file is not added, while the default_file_already_present is. Any ideas?
I've searched around, but can't find any decent documentation. I feel like I’m very close, so any help is much appreciated!
tl;dr - Adding files to system partition with makefile partially fails.

---

Solution!
For those who also run in to this problem:
As per Jean-Baptiste Quéru's post on a google group;
The Android makefiles are essentially split into 2 primary categories,
parsed in this order.
-the product definitions, which specify what modules need to be
installed for each product.
-the module definition, which specify how to build each module.
The build system protects itself against situation where you modify
the product definition from a module definition. PRODUCT_COPY_FILES is
part of the product definition, and can't be modify from a module
definition.
JBQ
Click to expand...
Click to collapse
What this means is that in order to copy files as is to the system image, we need to use product definitions.
What I did was first run ./build/envsetup.sh, in order to get access to commands like mgrep, etc.
I noticed that in frameworks/base/data/keyboards there was a keyboards.mk file, which got included correctly.
I made a copy and modifies it to suit my needs:
Code:
# Copyright (C) 2010 The Android Open Source Project
#
blah blah blah...
#
# This is the list of custom permissions to be injected in /system/etc/permissions
permissionsfiles := \
android.hardware.camera.front.xml \
android.hardware.usb.accessory.xml \
android.hardware.usb.host.xml \
android.hardware.wifi.direct.xml \
android.hardware.wifi.xml \
android.software.sip.voip.xml \
com.google.android.maps.xml \
com.google.android.media.effects.xml \
com.google.widevine.software.drm.xml \
handheld_core_hardware.xml \
platform_plus.xml \
features.xml
PRODUCT_COPY_FILES := $(foreach file,$(permissionsfiles),\
frameworks/base/data/etc/$(file):system/etc/permissions/$(file))
I ran "mgrep keyboards" and noted which makefiles included the keyboards.mk file, then I opened each file and duplicated that line, modifying it to instead include my custom_permissions.mk located in frameworks/base/data/etc/.
I compiled and the files were all there.
Hope this helps.