By convention, each package has two package names. In this text we
will refer to them as $pkg and $PKG.  The name
$pkg usually consists of lower case letters, digits, underlines
and hyphens. $PKG consists of uppercase letters, digits and
underlines, but no hyphens.  Normally $PKG is the name
$pkg with letters converted to upper case and hyphens
converted to underlines. Version numbers are not part of a package
name, so most package names don't contain digits.

Packages may be either library packages or binary packages.  Library
packages are in make/libs/*, while binary packages are in make/*.

Each package must define the following targets:

$(pkg)-download
	Download source for the package

${pkg}-source
${pkg}-unpacked
	Unpack source for the package

${pkg}-precompiled
	Compile package and prepare for firmware generation

${pkg}-clean
${pkg}-dirclean
	Remove all files that can be recreated

${pkg}-list
	add package to the list of static or dynamic patches

${pkg}-uninstall
	remove binary files from package or library files from root/${FREETZ_LIBRARY_DIR}


To use the convenience macros, you need some more defines:
# initialize package macros, ether BINary or LIBrary.
#   $(1) = version (mandatory)
#   $(2) = lower-case package name (optional, default name of makefile)
#   $(3) = upper-case package name (optional, default $2 converted to uppercase/underline)
# default values for
#  - $(PKG)_DIR : directory for sources
#  - $(PKG)_MAKE_DIR : directory for freetz makefile, patches and files
#  - $(PKG)_TARGET_DIR : directory for installation
BIN:
$(call PKG_INIT_BIN, VERSION, [pkg], [PKG])
LIB:
$(call PKG_INIT_LIB, VERSION, [pkg], [PKG])

# The download URL, split in directory part and filename
$(PKG)_SITE:=http://www.server.net/download
$(PKG)_SOURCE:=package-name-$($(PKG)_VERSION).tar.gz

# directory containing the makefiles. This value is the default from PKG_INIT.
# It should not be necessary to override this value.
$(PKG)_MAKE_DIR:=$(MAKE_DIR)/$(pkg)

# directory for sourcefile, "$($(PKG)_SOURCE_DIR)/" and the directory created by extracting the tar-file
# This value is the default from PKG_INIT.
$(PKG)_DIR:=$($(PKG)_SOURCE_DIR)/package-name-$($(PKG)_VERSION)

# target directory for the package. The default value depends on BIN/LIB,
# It should not be necessary to override this value.
BIN:
$(PKG)_TARGET_DIR:=$(PACKAGES_DIR)/$(pkg)-$($(PKG)_VERSION)
LIB:
$(PKG)_TARGET_DIR:=$(TARGET_SPECIFIC_ROOT_DIR)$(FREETZ_LIBRARY_DIR)

# root directory for installation. The default value depends on BIN/LIB,
# It should not be necessary to override this value.
BIN:
$(PKG)_TARGET_DIR:=$(PACKAGES_DIR)/$(pkg)-$($(PKG)_VERSION)/root
LIB:
$(PKG)_TARGET_DIR:=$(TARGET_SPECIFIC_ROOT_DIR)

# Order for inclusion in list of static or dynamic packages. Only for binary packages.
# Only necessary if the package contains a run-script
# The default is 99, which is intended for packages that have no run-script.
$(PKG)_STARTLEVEL=40


# Now you can use these macros:
# Download $($(PKG)_SITE)/$($(PKG)_SOURCE) to dl/$($(PKG)_SOURCE)
# defines $(pkg)-download
$(PKG_SOURCE_DOWNLOAD)

# Unpack binary or library package from dl/$($(PKG)_SOURCE) and apply patches
# defines $(pkg)-unpacked and $(pkg)-source
#
# Some packages contain suboptions. If $(PKG)_REBUILD_SUBOPTS is defined, the package is
# rebuild from scratch if one of the named options are changed in .config.
$(PKG_UNPACKED)

# configure package with ./configure with standard options
# common settings are read from include/site/*, a common config.cache is enabled.
# for special needs, use these macros:
#  - $(PKG)_CONFIGURE_PRE_CMDS
#    commands to execute before ./configure
#    terminate each command with ';'
#    example: $(PKG)_CONFIGURE_PRE_CMDS += autoconf --force ;
#  - $(PKG)_CONFIGURE_ENV
#    environment assignments before ./configure
#    example: $(PKG)_CONFIGURE_ENV += ac_cv_special_value=yes
#  - $(PKG)_CONFIGURE_OPTIONS
#    options for ./configure
#    example: $(PKG)_CONFIGURE_OPTIONS += --with-foo --enable-bar
$(PKG_CONFIGURED_CONFIGURE)

# If the package has no configuration, use this
$(PKG_CONFIGURED_NOP)

# Finalize package
# defines ${pkg}-list for binary packages
# defines $(pkg)-dirclean
$(PKG_FINISH)