Re: [gentoo-dev] ebuild optional dependancy question

[Bob Phan]

On Mon, 11 Mar 2002, Brian M. Rzycki wrote:

> The second program (yafc -- yafc.sourceforge.net) is not as
> straightforward as zile.  For the uninitiated, yafc is an interactive
> ftp client similar to lftp with support for socks4/5, kerberos4/5, and
> sftp.  Yafc's configure script automatically enables/disables ssh and
> readline if it finds the libraries.  The same is not true for socks and
> kerberos.  I merged kth-krb (kerberos4) and saw it installed everything in
> /usr/athena.  When I manually gave configure the parameter
> --with-krb4=/usr/athena it compiled with kerberos4 support.  I had similar
> results with dante (socks4/5).
>
> After discovering I had to manually apply parameters to the configure
> script in order for socks/kerberos support I went looking for use
> variables. I planned on using the "if [ -z "use_var" ]" trick from the
> gentoo-howto.  Unfortunately I didn't see either socks or krb4/5 use
> variables.
>
> So my question is this:  What is the correct gentoo way of discovering
> these packages?  Should I consult /var/db/pkg/app_group/app_name* to see
> if the program is installed?  Should I check the physical location for
> the libraries (a la -d /usr/athena)?  Or am I just a numbskull and
> missing some obvious feature of portage which makes my life much easier?

I was actually planning on making a yafc ebuild myself :).  Anyway, you
want to use the notation like this (which is all in the developer howto):

DEPEND="...
        lots of usual stuff
        ...
        NAME_OF_USE_VAR? ( >=category/package-version_number )

for example:

        krb4? ( >=app-crypt/kth-krb-1.1-r1 )
 
Then, in the src_compile secion of the ebuild, you want to put:

local myopts

if [ -n "`use krb4`" ]
then
        myopts="${myopts} --with-krb4"
fi

./configure \
        ${myopts}

You might want to read some other ebuilds to get a good feel as to how
this works.

Disclaimer:
I'm not a gentoo developer, so my suggestions are subject to critisizm.
Also, krb4 is not a recognized USE parameter.  You might want to ask an
official gentoo developer how that should be handled, perhaps there should
be an official gentoo USE parameter for kerberos 4 and 5.  My suggestion
is krb4 and krb5, but that's just my suggestion.

Hope this was helpful.

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