How to Build a single module in Android and include in System image

Go to build directory under Android sources
Execute source ./envsetup.sh
Go to corresponding application directory (~/eclair/hardware/msm7k/libaudio$)
Issue mm command to build the Module only in this case its libaudio.so

if you want to include in system.img in conjunction with ROM sources from vendor

run make from the root directory

~/eclair$ make
============================================
PLATFORM_VERSION_CODENAME=REL
PLATFORM_VERSION=2.1-update1
TARGET_PRODUCT=generic
TARGET_BUILD_VARIANT=eng
TARGET_SIMULATOR=
TARGET_BUILD_TYPE=release
TARGET_ARCH=arm
HOST_ARCH=x86
HOST_OS=linux
HOST_BUILD_TYPE=release
BUILD_ID=ECLAIR
============================================
build/core/copy_headers.mk:15: warning: overriding commands for target `out/target/product/generic/obj/include/libpv/getactualaacconfig.h'
build/core/copy_headers.mk:15: warning: ignoring old commands for target `out/target/product/generic/obj/include/libpv/getactualaacconfig.h'
Install: out/host/linux-x86/lib/libneo_util.so
...
...
...
Install system fs image: out/target/product/generic/system.img
~/eclair$