* fixes for RISC-V ABI Implementation #1567
Fixed RISC-V floating-point ABI by correcting the target triple to
`riscv64-unknown-linux-gnu`, adding the `target-abi` module flag, and
ensuring ABI-required CPU features are enabled.
I tested this with:
```bash
build/c3c compile-only --target linux-riscv64 rv_hello.c3
readelf -h obj/linux-riscv64/rv_hello.o | grep Flags
# Output: Flags: 0x5, RVC, double-float ABI
```
```bash
# and qemu because I don't have a riscv machine :/
qemu-riscv64-static -L /usr/riscv64-linux-gnu ./rv_hello
```
---
@lerno I purposedly left these two failing tests to clearly see the
difference.
`test/test_suite/abi/riscv64-lp64-lp64f-abi-1.c3t`
`test/test_suite/abi/riscv64-lp64-abi.c3t`
* improve Linux cross-compilation, specifically for RISC-V
- Implement automatic sysroot and CRT object discovery for RISC-V.
- Fix dynamic linker paths and emulation flags for LLD.
- Link against libgcc to resolve required arithmetic symbols.
* Update tests.
* fix linker CRT detection by centralizing host arch check
use target_host_arch() in linker.c
move target_host_arch() from hostinfo.c to target.c
* missing debug info
---------
Co-authored-by: Christoffer Lerno <christoffer@aegik.com>