Synchronize gcc-compat branch

[kheersagarpatel]

Summary

Synchronization update for the gcc-compat branch.

Changes

Branch Updates

• What: Integrated the latest branch updates and resolved integration changes.
• Why: Maintain a consistent development state across ongoing work.

General

• What: Consolidated the current state of development.
• Why: Prepare the branch for continued development and review.

Compatibility

• Existing functionality is unchanged (or breaking changes are explicitly documented).
• MSVC/Windows build compatibility not verified as part of this synchronization.
• GCC/Linux build toolchain remains compatible.
• Runtime compatibility across all supported platforms has not been fully revalidated.

Related

Part of #44.

[kheersagarpatel]

Commit: 2e18e5a

Summary

Improve the CI workflow to better support GCC and LLVM builds and streamline ARM64 build validation.

Changes

GitHub Actions

• Added gcc-compat as a workflow trigger for push and pull request events.
• Consolidated Linux builds into a compiler matrix for GCC and LLVM.
• Added GNU-EFI caching to reduce CI build time.

Linux Build

• Added Clang/LLD installation for LLVM builds.
• Updated BootAA64 build steps to select the appropriate toolchain.
• Updated KernelAA64 build steps to select the appropriate toolchain.
• Added make clean before each build to ensure clean build validation.

Compatibility

• Existing workflow behavior is preserved.
• GCC build path verified.
• LLVM build path added.
• MSVC workflow changes not revalidated as part of this update.

Related

Part of #44.