Add two versions of std math library, libcsm and phoenix

[ayoopierre]

Adding libmcs library, and tools for phoenix build system to select math library to build on (either libmcs or libphoenix implementation).

Description

Adding files from libmcs, move math files from libphoenix to core-libs, create new Makefile

Motivation and Context

Add math library for critical applications.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (refactoring, style fixes, git/CI config, submodule management, no code logic changes)

All projects, that depend on math library should add appropriate flag for linking against new library

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: (all targets except for ia32 - new library causes compilation error due to patches on micropython).

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
• I will merge this PR by myself when appropriate.

[gemini-code-assist]

Summary of Changes

Hello @ayoopierre, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the project's mathematical capabilities by integrating a new, highly configurable standard math library. It provides the flexibility to choose between two distinct implementations, libmcs for critical applications and the existing libphoenix math, directly within the build system. This change is foundational, impacting how dependent projects link against the math library.

Highlights

• New Math Library Integration: Introduced libm as a new component in the build system, allowing selection between libmcs and libphoenix math implementations.
• libmcs Library Addition: Incorporated the libmcs (Mathematical Library for Critical Systems) with its full source code, build scripts, and comprehensive documentation.
• Build System Flexibility: The build system now supports conditional compilation, enabling users to choose their preferred math library implementation via a USE_LIBMCS flag.
• Breaking Change: Projects dependent on the math library will need to update their linking flags to accommodate the new library selection mechanism.

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[gemini-code-assist]

Code Review

This pull request introduces the libmcs math library and integrates it into the build system. The changes are extensive, including the library's source code, build scripts, and documentation. While the overall structure is good, there are several issues in the Makefiles and CI configuration that need attention. Specifically, the libm/Makefile has issues with installing source files as headers, inconsistent indentation, and a typo. The .gitlab-ci.yml file has a potential race condition due to incorrect job dependencies. Additionally, there's a code style improvement suggested for a header file to avoid code bloat.

[agkaminski]

• pls add JIRA ID to commit msg
• add library in a separate commit from additional changes

[github-actions]

Unit Test Results

9 277 tests  +63   8 687 ✅ +62   55m 5s ⏱️ +38s
  545 suites + 9     589 💤 ± 0 
    1 files   ± 0       1 ❌ + 1 

For more details on these failures, see this check.

Results for commit ac6284d. ± Comparison against base commit 82ac411.

♻️ This comment has been updated with latest results.

[nalajcie]

• .clang-format should be added to the dir with external code (either ignore all formatting rules or provide other coding style if available in upstream project )
• you can disable shellcheck for full files by adding a directive in a header (probably #shellcheck disable=all) - you may add them in a separate commit
• sooo, we need to have separate header files for different libc implementations? (shame)
• does this change break toolchain multilib building (libm needs to be installed in toolchain, probably libm headers need to be available also for building libstdc++)?