It is easy to add a new package to BuiltRoot, here I want to add
opkg to BuildRoot
1. read the documents in the builtroot-2012.02/docs/manual/adding-packages-*
2. add a new directory in the builtroot-2012.02/package, name it as opkg
#mkdir builtroot-2012.02/package/opkg
3. add Config.in in the builtroot-2012.02/package/opkg
#gedit builtroot-2012.02/package/opkg/Config.in
config BR2_PACKAGE_OPKG
bool "opkg"
help
Opkg is a lightweight package management system based on Ipkg.
http://code.google.com/p/opkg/
4. add opkg.mk in the the builtroot-2012.02/package/opkg
#gedit the builtroot-2012.02/package/opkg/opkg.mk
#############################################################
#
# opkg
#
#############################################################
OPKG_VERSION = 0.1.8
OPKG_SOURCE = opkg-$(OPKG_VERSION).tar.gz
OPKG_SITE = http://opkg.googlecode.com/files/
OPKG_AUTORECONF = NO
OPKG_INSTALL_STAGING = YES
OPKG_INSTALL_TARGET = YES
OPKG_CONF_OPT = --disable-pgp
$(eval $(call AUTOTARGETS))
5. modify Config.in in builtroot-2012.02/package
add "source "package/opkg/Config.in"" in line 530
6. return to directory builtroot-2012.02, make menuconfig again to enable theopkg
#make menuconfig
Package Selection for the target -> Package managers -> opkg
7. make the buildroot again
#make