[yocto] Using PACKAGECONFIG

[Gary Thomas]

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?

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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