[RFC] providers.sh: versionVariableMatch: use the name of provided item instead of pn

* when checking for PREFERRED_VERSION and REQUIRED_VERSION use
  the name of the preferred item, not the pn of the provider

* sending as RFC, because there might be some other uses of
  this function where the old behavior was better

* the case where this seems to work incorrectly is meta-clang clang recipe
  which correctly says:

  conf/layer.conf:LLVMVERSION = "15.0.7"
  conf/layer.conf:PREFERRED_PROVIDER_llvm-native = "clang-native"
  recipes-devtools/clang/clang_git.bb:PROVIDES:append:class-native = " llvm-native"

  LLVMVERSION is used by oe-core as:
  meta/conf/distro/include/tcmode-default.inc:LLVMVERSION ?= "15.%"
  meta/conf/distro/include/tcmode-default.inc:PREFERRED_VERSION_llvm = "${LLVMVERSION}"
  meta/conf/distro/include/tcmode-default.inc:PREFERRED_VERSION_llvm-native = "${LLVMVERSION}"
  meta/conf/distro/include/tcmode-default.inc:PREFERRED_VERSION_nativesdk-llvm = "${LLVMVERSION}"

  and now this code will cause a warning about 15.0.7 version not being available
  even when in the end it will use clang-native as a provider with this version:

  $ bitbake-getvar -r llvm-native PV 2>&1 | tee log.bitbake-getvar.llvm-native-4
  WARNING: preferred version 15.0.7 of llvm-native not available (for item llvm-native)
  WARNING: versions of llvm-native available: 15.0.6
  #
  # $PV [4 operations]
  #   set oe-core/meta/conf/bitbake.conf:239
  #     "${@bb.parse.vars_from_file(d.getVar('FILE', False),d)[1] or '1.0'}"
  #   set oe-core/meta/conf/documentation.conf:340
  #     [doc] "The version of the recipe. The version is normally extracted from the recipe filename."
  #   set oe-core/meta/classes-global/sstate.bbclass:51
  #     [vardepvalue] "${PV}"
  #   set meta-clang/recipes-devtools/clang/clang.inc:13
  #     "${MAJOR_VER}.${MINOR_VER}.${PATCH_VER}"
  # pre-expansion value:
  #   "${MAJOR_VER}.${MINOR_VER}.${PATCH_VER}"
  PV="15.0.7"

  the problem is that both llvm-native from oe-core and clang-native are
  found as possible providers for item llvm-native, but then we call
  findPreferredProvider for pkg_pn clang-native, we'll check for
  PREFERRED_VERSION_clang_native not PREFERRED_VERSION_llvm-native

  then when running findPreferredProvider for pkg_pn llvm-native
  we find the PREFERRED_VERSION_llvm-native and if it doesn't
  match with PV we issue the warning, be aware that this issue
  is reproducible only when they don't happen to match, e.g. with
  master before:
  https://git.openembedded.org/openembedded-core/commit/?id=7438f9a9efaf0826f1be13acbc51f0a1134cf175
  in dunfell it's triggered as well, with different versions:

  WARNING: preferred version 14.0.3 of llvm-native not available (for item llvm-native)
  WARNING: versions of llvm-native available: 13.0.1

* if we agree that this is something worth changing, then the
  search for available versions should be similarly changed
  as well, because now in dunfell it shows only 13.0.1
  while clang-native-14.0.3 is also available provider for
  it (and actually gets used in the end).

* this might make some sense for llvm-native and clang-native
  but I can imagine counter example when you have 2 very different
  providers for something and you want to control their versions
  independently from which provider is preferred e.g. by MACHINE.conf

* this change didn't cause any new warnings in my builds, but other
  layers might be more creative with P_V/P_P

* alternative solution might be to use different variable name
  in meta-clang/conf/layer.conf to avoid changing llvm-native P_V
  and depend on P_P to always select clang recipes to provide llvm
  which might be less controversial than this P_V behavoir change

  I have a local commit which changes LLVMVERSION to CLANGLLVMVERSION
  in these 3 meta-clang places:
  conf/layer.conf:LLVMVERSION = "14.0.3"
  dynamic-layers/openembedded-layer/recipes-devtools/bcc/bcc_0.24.0.bb:    -DLLVM_PACKAGE_VERSION=${LLVMVERSION} \
  dynamic-layers/openembedded-layer/recipes-devtools/bpftrace/bpftrace_0.14.1.bb:    pvsplit = d.getVar('LLVMVERSION').split('.')

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
---
 lib/bb/providers.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)