pyenv shim handling with BitBake

[chris-laplante]

This is meant to be a continuation of the discussion in #2696.

As a status update, with the infinite recursion fix (from @native-api) in place, I now get an error message as opposed to a hang:

WARNING: file-5.46-r0 do_fetch: Failed to fetch URL git://github.com/file/file.git;branch=master;protocol=https, attempting MIRRORS if available
WARNING: file-5.46-r0 do_fetch: Unable to get top level for /home/laplante/repos/bitbake/bitbake-builds/.bitbake-setup-downloads/git2/github.com.file.file.git (not a git directory?): Fetcher failure: Fetch command export PSEUDO_DISABLED=1; export SSL_CERT_DIR="/etc/ssl/certs"; export SSL_CERT_FILE="/etc/ssl/certs/ca-certificates.crt"; export DBUS_SESSION_BUS_ADDRESS="unix:path=/run/user/1000/bus"; export GIT_SSL_CAINFO="/etc/ssl/certs/ca-certificates.crt"; export PATH="/home/laplante/repos/bitbake/bitbake-builds/poky-master/build/tmp/sysroots-uninative/x86_64-linux/usr/bin:/home/laplante/repos/bitbake/bitbake-builds/poky-master/layers/openembedded-core/scripts:/home/laplante/repos/bitbake/bitbake-builds/poky-master/build/tmp/work/cortexa76-poky-linux/file/5.46/recipe-sysroot-native/usr/bin/aarch64-poky-linux:/home/laplante/repos/bitbake/bitbake-builds/poky-master/build/tmp/work/cortexa76-poky-linux/file/5.46/recipe-sysroot/usr/bin/crossscripts:/home/laplante/repos/bitbake/bitbake-builds/poky-master/build/tmp/work/cortexa76-poky-linux/file/5.46/recipe-sysroot-native/usr/sbin:/home/laplante/repos/bitbake/bitbake-builds/poky-master/build/tmp/work/cortexa76-poky-linux/file/5.46/recipe-sysroot-native/usr/bin:/home/laplante/repos/bitbake/bitbake-builds/poky-master/build/tmp/work/cortexa76-poky-linux/file/5.46/recipe-sysroot-native/sbin:/home/laplante/repos/bitbake/bitbake-builds/poky-master/build/tmp/work/cortexa76-poky-linux/file/5.46/recipe-sysroot-native/bin:/home/laplante/repos/bitbake/bitbake-builds/poky-master/layers/bitbake/bin:/home/laplante/repos/bitbake/bitbake-builds/poky-master/build/tmp/hosttools"; export HOME="/home/laplante"; LANG=C git -c gc.autoDetach=false -c core.pager=cat -c safe.bareRepository=all -c clone.defaultRemoteName=origin rev-parse --absolute-git-dir failed with exit code 127, output:
pyenv: python3: command not found

The `python3' command exists in these Python versions:
  3.5.10
  3.12.8
  3.13.1
  pypy3.10-7.3.17
  pypy3.11-7.3.20

Note: See 'pyenv help global' for tips on allowing both
      python2 and python3 to be found.

[native-api]

It just dawned on me that pyenv exec --no-shims (suggested in #2696 (comment)) should just work!

Since it would prepend <selected version>/bin to the PATH of the executed command (and doesn't prepend anything if system is selected) -- whether you have an alternate installation or not, the corresponding real executables would be the first on PATH that bitbake would be using.