[package] autoconf/2.71 does not work with Conan 2.0

[System-Arch]

Description

The autoconf recipe was nominally ported to Conan 2.0 but had an incompatible workaround for conan-io/conan#12499. Now that the fix for that issue has been released with Conan, we can remove the workaround so that the recipe works with Conan 2.0

Package and Environment Details

Package Name/Version: autoconf/2,71
Operating System+version: Debian 10
Compiler+version: gcc 8
Conan version: conan 2.0.0-beta6
Python version: Python 3.7.3

Conan profile

Profile host:
[settings]
arch=x86_64
build_type=Release
compiler=gcc
compiler.libcxx=libstdc++11
compiler.version=8
os=Linux
[options]
cmake*:bootstrap=True
[tool_requires]
!openssl*: cmake/3.24.2

Steps to reproduce

conan-2.0 source --name autoconf --version 2.71 .

Logs

Click to expand log

conan-2.0 source --name autoconf --version 2.71 .
ERROR: Error loading conanfile at '/tmp/tmp.5VWf08gJrQ/autoconf/conanfile.py': Unable to load conanfile in /tmp/tmp.5VWf08gJrQ/autoconf/conanfile.py
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/tmp/tmp.5VWf08gJrQ/autoconf/conanfile.py", line 7, in <module>
    from conans import tools as tools_legacy
ImportError: cannot import name 'tools' from 'conans' (/mathworks/devel/sandbox/marc/conan-2.0/conan-io/conans/__init__.py)```

</details>

[System-Arch]

I will submit a fix shortly.

[SpaceIm]

The fix you refer on has been released in conan 1.55.0, but c3i runs conan 1.54.0. Moreover I'm not even sure it fixes the issue we had after autoconf migration (which is that buildenv vars defined as paths in package_info() are not converted with unix_path() if recipe is consumed as build requirement in another recipe enabling win_bash, regardless of editable mode).

[AbrilRBS]

Woops, sorry that we didn't give you a heads-up sooner, but autoconf has now been ported for a bit, let us know if you find any problems with it :)