[Buildroot] [PATCH 3/5] doc: more details about expressing dependencies in Config.in

[Michael S. Zick <minimod@morethan.org>]

On Sun November 13 2011, Thomas Petazzoni wrote:
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> ---
>  docs/manual/adding-packages-directory.txt |   45 +++++++++++++++++++++++++++++
>  1 files changed, 45 insertions(+), 0 deletions(-)
> 
> diff --git a/docs/manual/adding-packages-directory.txt b/docs/manual/adding-packages-directory.txt
> index b61eb54..a6b1f17 100644
> --- a/docs/manual/adding-packages-directory.txt
> +++ b/docs/manual/adding-packages-directory.txt
> @@ -46,6 +46,51 @@ supposed to contain anything but the 'bare' name of the package.
>  source "package/libfoo/Config.in"
>  --------------------------
>  
> +The +Config.in+ file of your package must also ensure that
> +dependencies are also enabled. Typically, Buildroot uses the following
> +rules:
> +
> +* Use a +select+ type of dependency for dependencies on
> +  libraries. These dependencies are generally not obvious and it
> +  therefore make sense to have the kconfig system ensure that the

s/therefore make sense to have/is sensible that/

Mike
> +  dependencies are selected. For example, the _libgtk2_ package uses
> +  +select BR2_PACKAGE_LIBGLIB2+ to make sure this library is also
> +  enabled.
> +
> +* Use a +depends on+ type of dependency when the user really needs to
> +  be aware of the dependency. Typically, Buildroot uses this type of
> +  dependency for dependencies on toolchain options (large file
> +  support, RPC support, IPV6 support), or for dependencies on "big"
> +  things, such as the X.org system. In some cases, especially
> +  dependency on toolchain options, it is recommended to add a
> +  +comment+ displayed when the option is not enabled, so that the user
> +  knows why the package is not available.
> +
> +An example illustrates both the usage of +select+ and +depends on+.
> +
> +--------------------------
> +config BR2_PACKAGE_ACL
> +        bool "acl"
> +        select BR2_PACKAGE_ATTR
> +        depends on BR2_LARGEFILE
> +        help
> +          POSIX Access Control Lists, which are used to define more
> +          fine-grained discretionary access rights for files and
> +          directories.
> +          This package also provides libacl.
> +
> +          http://savannah.nongnu.org/projects/acl
> +
> +comment "acl requires a toolchain with LARGEFILE support"
> +        depends on !BR2_LARGEFILE
> +--------------------------
> +
> +
> +Note that such dependencies will make sure that the dependency option
> +is also enabled, but not necessarily built before your package. To do
> +so, the dependency also needs to be expressed in the +.mk+ file of the
> +package.
> +
>  The +.mk+ file
>  ~~~~~~~~~~~~~~
>