Major Features:
- Multi-compiler/linker configuration system with toolchain support
- Auto-manage Secure C (libboundscheck) dependency
- Dynamic provider library names for CMVP modes (ISO19790, SM)
- macOS/Darwin platform support with unified POSIX abstractions
- Cross-platform build improvements and optimizations
Build System:
- Add toolchain management for cross-compilation
- Support nested 'common' format in compile config
- with _EXTRA/_REMOVE/_OVERRIDE in common flags, we can add remove by
per compiler
- Unify toolchain naming convention (arch-vendor-os-abi-compiler)
Platform Support:
- Unify Linux and Darwin sources under POSIX
- Add Darwin support for SAL and build flags
- Add Darwin support for REC wrapper functions (WIP)
- Cross-platform ops count macros for benchmarking
- Platform-specific library extension detection (.dylib vs .so)
Cherry-picked from: https://gitcode.com/openHiTLS/openhitls/merge_requests/652
Signed-off-by: Dongjianwei001 <dongjianwei1@huawei.com>