llvm-core: unpin cmake version

[pierricgimmig]

In llvm-core, the cmake version was pinned to 3.20.5, making it impossible to build with VS 2022 on Windows since VS 2022 generators were introduced with cmake 3.21. From the original comment, it seems the intention was not to pin cmake, but rather specify a minimum version.

This change simply transforms the cmake pinning to a mere minimum requirement, making it possible to compile llvm-core with toolchains born after cmake 3.20.5.

Specify library name and version: llvm-core/all

---

• I've read the contributing guidelines.
• I've used a recent Conan client version close to the currently deployed.
• I've tried at least one configuration locally with the conan-center hook activated.

[CLAassistant]

All committers have signed the CLA.

[github-actions]

🤖 Beep Boop! This pull request is making changes to 'recipes/llvm-core//'.

👋 @Hopobcn @paulharris you might be interested. 😉

[RubenRBS]

Hi! Thanks a lot for taking the time to fix this issue, we really appreciate it

Please remember to request access by writing in #4 before we can merge this PR, after that the PR will be picked automatically once we leave maintenance mode in the CI systems, so no need for further actions on your part :)

[pierricgimmig]

Hi @RubenRBS , do I need to do somehting more on my end? Thanks!

[conan-center-bot]

Conan v1 pipeline ❌

Failure in build 4 (02e77d101f6368561095d6dcd0a716e1acc9163d):

• llvm-core/13.0.0:
  Didn't run or was cancelled before finishing

• llvm-core/12.0.0:
  Didn't run or was cancelled before finishing

• llvm-core/11.1.0:
  CI failed to create some packages (All logs)

  Logs for packageID 4c51afa229aaa3c8ad242697883866f3a5d2a1f0:

  [settings]
  arch=armv8
  build_type=Release
  compiler=apple-clang
  compiler.libcxx=libc++
  compiler.version=13.0
  os=Macos
  [options]
  llvm-core:shared=False
  

  [...]
  
  ----Running------
  > cmake --build '/Users/jenkins/workspace/prod-v1/bsr/cci-20e63ab6/recipes/llvm-core/all/test_package/build/2ed3211b8b7c487f797461697d7a301127db8466' '--' '-j8'
  -----------------
  [ 50%] Building CXX object CMakeFiles/test_package.dir/test_package.cpp.o
  [100%] Linking CXX executable bin/test_package
  CMake Warning:
    Manually-specified variables were not used by the project:
  
      CMAKE_EXPORT_NO_PACKAGE_REGISTRY
      CMAKE_INSTALL_BINDIR
      CMAKE_INSTALL_DATAROOTDIR
      CMAKE_INSTALL_INCLUDEDIR
      CMAKE_INSTALL_LIBDIR
      CMAKE_INSTALL_LIBEXECDIR
      CMAKE_INSTALL_OLDINCLUDEDIR
      CMAKE_INSTALL_SBINDIR
  
  
  Undefined symbols for architecture arm64:
    "_LLVMInitializeAArch64Target", referenced from:
        _main in test_package.cpp.o
    "_LLVMInitializeAArch64TargetInfo", referenced from:
        _main in test_package.cpp.o
    "_LLVMInitializeAArch64TargetMC", referenced from:
        _main in test_package.cpp.o
  ld: symbol(s) not found for architecture arm64
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  make[2]: *** [bin/test_package] Error 1
  make[1]: *** [CMakeFiles/test_package.dir/all] Error 2
  make: *** [all] Error 2
  WARN: *** Conan 1 is legacy and on a deprecation path ***
  WARN: *** Please upgrade to Conan 2 ***
  WARN: libxml2/2.9.10: requirement zlib/[>=1.2.11 <2] overridden by llvm-core/11.1.0 to zlib/1.2.12 
  llvm-core/11.1.0 (test package): WARN: 
       ************************************************
       The 'cmake_find_package' generator is deprecated.
       Please update your code and remove it.
       *************************************************
  
  llvm-core/11.1.0 (test package): WARN: 
       ************************************************
       The 'cmake' generator is deprecated.
       Please update your code and remove it.
       *************************************************
  
  llvm-core/11.1.0 (test package): WARN: **** The 'from conans import CMake' helper is deprecated. Please update your code and remove it. ****
  ERROR: llvm-core/11.1.0 (test package): Error in build() method, line 13
  	build_system.build()
  	ConanException: Error 2 while executing cmake --build '/Users/jenkins/workspace/prod-v1/bsr/cci-20e63ab6/recipes/llvm-core/all/test_package/build/2ed3211b8b7c487f797461697d7a301127db8466' '--' '-j8'
  

---

^{Note: To save resources, CI tries to finish as soon as an error is found. For this reason you might find that not all the references have been launched or not all the configurations for a given reference. Also, take into account that we cannot guarantee the order of execution as it depends on CI workload and workers availability.}

---

Conan v2 pipeline ❌

Note: Conan v2 builds are now mandatory. Please read our discussion about it.

The v2 pipeline failed. Please, review the errors and note this is required for pull requests to be merged. In case this recipe is still not ported to Conan 2.x, please, ping @conan-io/barbarians on the PR and we will help you.

See details:

Failure in build 4 (02e77d101f6368561095d6dcd0a716e1acc9163d):

• llvm-core/13.0.0:
  Error running command conan export --name llvm-core --version 13.0.0 recipes/llvm-core/all/conanfile.py:

  ======== Exporting recipe to the cache ========
  ERROR: Error loading conanfile at '/home/conan/workspace/prod-v2_cci_PR-23404/recipes/llvm-core/all/conanfile.py': Unable to load conanfile in /home/conan/workspace/prod-v2_cci_PR-23404/recipes/llvm-core/all/conanfile.py
    File "<frozen importlib._bootstrap_external>", line 728, in exec_module
    File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
    File "/home/conan/workspace/prod-v2_cci_PR-23404/recipes/llvm-core/all/conanfile.py", line 6, in <module>
      from conans import CMake
  ImportError: cannot import name 'CMake' from 'conans' (/opt/pyenv/versions/3.7.17/lib/python3.7/site-packages/conans/__init__.py)
  

• llvm-core/12.0.0:
  Error running command conan export --name llvm-core --version 12.0.0 recipes/llvm-core/all/conanfile.py:

  ======== Exporting recipe to the cache ========
  ERROR: Error loading conanfile at '/home/conan/workspace/prod-v2_cci_PR-23404/recipes/llvm-core/all/conanfile.py': Unable to load conanfile in /home/conan/workspace/prod-v2_cci_PR-23404/recipes/llvm-core/all/conanfile.py
    File "<frozen importlib._bootstrap_external>", line 728, in exec_module
    File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
    File "/home/conan/workspace/prod-v2_cci_PR-23404/recipes/llvm-core/all/conanfile.py", line 6, in <module>
      from conans import CMake
  ImportError: cannot import name 'CMake' from 'conans' (/opt/pyenv/versions/3.7.17/lib/python3.7/site-packages/conans/__init__.py)
  

• llvm-core/11.1.0:
  Error running command conan export --name llvm-core --version 11.1.0 recipes/llvm-core/all/conanfile.py:

  ======== Exporting recipe to the cache ========
  ERROR: Error loading conanfile at '/home/conan/workspace/prod-v2_cci_PR-23404/recipes/llvm-core/all/conanfile.py': Unable to load conanfile in /home/conan/workspace/prod-v2_cci_PR-23404/recipes/llvm-core/all/conanfile.py
    File "<frozen importlib._bootstrap_external>", line 728, in exec_module
    File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
    File "/home/conan/workspace/prod-v2_cci_PR-23404/recipes/llvm-core/all/conanfile.py", line 6, in <module>
      from conans import CMake
  ImportError: cannot import name 'CMake' from 'conans' (/opt/pyenv/versions/3.7.17/lib/python3.7/site-packages/conans/__init__.py)
  

---

^{Note: To save resources, CI tries to finish as soon as an error is found. For this reason you might find that not all the references have been launched or not all the configurations for a given reference. Also, take into account that we cannot guarantee the order of execution as it depends on CI workload and workers availability.}