couple questions on PACKAGECONFIG (for improving docs)

["rpjday@crashcourse.ca" <rpjday@crashcourse.ca>]

  wanted to tweak the ref manual entry for PACKAGECONFIG, so a couple
issues. first, the ref manual entry:

https://www.yoctoproject.org/docs/current/ref-manual/ref-manual.html#var-PACKAGECONFIG

says nothing about the possible *sixth* entry, described in
base.bbclass as "foo_conflict_packageconfig", so i can add that but
i'm open to proper wording since i'd probably screw it up.
(i'd add an actual example from poky/ demonstrating this, such as:

meta/recipes-support/curl/curl_7.69.1.bb:PACKAGECONFIG[threaded-resolver]
  = "--enable-threaded-resolver,--disable-threaded-resolver,,,,ares"

  i'd be tempted to show some of the simpler variations of
PACKAGECONFIG, such as (if i read it correctly) being equivalent to
simply adding RDEPENDS values (right?):

meta/recipes-support/boost/boost.inc:PACKAGECONFIG[graph_parallel] =
  ",,,boost-mpi mpich"

  finally, i'd toss in explaining this, which might confuse people:

meta/recipes-multimedia/pulseaudio/pulseaudio.inc:PACKAGECONFIG[autospawn-for-root]
  = ",,,"

i'm betting some developers might wonder what that is all about and,
for every example i've seen for that, it involves *something*
explicitly checking for that config setting somewhere in the recipe,
as in the case above:

do_compile_append () {
  if ${@bb.utils.contains('PACKAGECONFIG', 'autospawn-for-root', 'true', 'false', d)}; then
    set_cfg_value src/client.conf allow-autospawn-for-root yes
  fi
}

  all that make sense?

rday