[yocto] Using PACKAGECONFIG

[Paul Eggleton]

Hi Gary,

On Thursday 09 April 2015 07:45:47 Gary Thomas wrote:
> I'm trying to extend PACKAGECONFIG for a recipe (vlc).  The
> main recipe contains this:
>    PACKAGECONFIG ?= " live555"
>    PACKAGECONFIG[mad] = "--enable-mad,--disable-mad,libmad"
>    PACKAGECONFIG[a52] = "--enable-a52,--disable-a52,liba52"
>    PACKAGECONFIG[jack] = "--enable-jack,--disable-jack,jack"
>    PACKAGECONFIG[live555] = "--enable-live555,--disable-live555,live555"
>    PACKAGECONFIG[libass] = "--enable-libass,--disable-libass,libass"
>    PACKAGECONFIG[mkv] = "--enable-mkv,--disable-mkv,libmatroska libebml"
>    PACKAGECONFIG[postproc] =
> "--enable-postproc,--disable-postproc,libpostproc" PACKAGECONFIG[opencv] =
> "--enable-opencv,--disable-opencv,opencv" PACKAGECONFIG[libva] =
> "--enable-libva --enable-avcodec,--disable-libva --disable-avcodec,libva
> libav"
> 
> I'd like to only add "libva" to the default, so I wrote this
> in my local.conf:
>    PACKAGECONFIG_pn-vlc_append = " libva"
> Inspecting it
>    $ bitbake vlc -e | grep ^PACKAGECONFIG
>    PACKAGECONFIG=" libva"
> 
> Oops.  Just to be sure, I tried
>    PACKAGECONFIG_pn-vlc = "live555 libva"
> which gives
>    $ bitbake vlc -e | grep ^PACKAGECONFIG
>    PACKAGECONFIG="live555 libva"
> 
> Note: I tried
>    PACKAGECONFIG_append_pn-vlc = " libva"
> which does work.  However, I've also used
>    PACKAGECONFIG_pn-chromium_append = " component-build"
> for a different recipe that does work... VERY CONFUSED
> 
> What am I doing wrong?  How do I correctly add to the default list?

In general, for a conditional append, you must use _append_<override> - the 
other way around will not do an append, AFAIK it will just set the value.

There are some other valid options that you didn't mention above:

1) Set it outright to list all of the options you want instead of appending. 
At least you know exactly what is going into the value. (I know some people 
don't like this.)

2) Set it using += or _append from a bbappend.

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre