Building Zig applications on sim:x86_64 with Zig 0.13.0 fails because
the generated target "x86_64-freestanding-sysv" is not recognized by
Zig. Introduce a Zig-specific ABI mapping that translates "sysv" to
"gnu" without affecting other toolchains.
After correcting the target ABI, linking still fails due to unresolved
references to __zig_probe_stack. Add -fcompiler-rt so Zig includes the
required compiler runtime during linking.
Verified on sim:nsh with CONFIG_EXAMPLES_HELLO_ZIG=y:
nsh> hello_zig
[sim]: Hello, Zig!
Fixes#19475
Signed-off-by: Ansh Rai <anshrai331@gmail.com>
