metaelf: provide elf.h alternative on macOS

[gerard5]

Description

This change provides alternative source for elf.h on macOS host, on which, the missing elf.h dependency can be replaced with libelf, which after package installation, can be found in /usr/local/include and /usr/local/lib.

Install libelf using brew:

brew install libelf

JIRA: RTOS-580

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue) Fixes https://github.com/phoenix-rtos/phoenix-rtos-project/issues/701
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

How Has This Been Tested?

• [ ] Already covered by automatic testing.
• [ ] New test added: (add PR link here).
• [x] Tested by hand on: macOS.

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.