darwin/amd64: _demo/go/readdir fails due syscall trampoline ABI mismatch

[luoliwoshang]

Summary

On macOS Intel (darwin/amd64), _demo/go/readdir can fail with corrupted directory entries when built/run by llgo.

Reproduction

cd _demo/go/readdir
llgo run .

Observed behavior (intermittent/runner-dependent):

• empty or corrupted entry names
• panic like Bad readdir entries go.mod/go.sum

Scope

• Reproduced on darwin/amd64
• Other matrix targets did not show the same failure

Root Cause

The Darwin syscall trampoline call path in llgo uses uintptr ABI assumptions.
fdopendir/closedir/readdir_r were not consistently routed through ABI-safe wrappers, leading to symbol/ABI mismatch in this path and corrupted dirent reads.

Expected

_demo/go/readdir should consistently print valid entry names and must not panic.

Tracking

Fix is included in PR #1655.

[cpunion]

I re-checked this against current main (eda01de3).

I could not strictly reproduce or disprove it on my current machine because the reported failure is specific to darwin/amd64, while my host is darwin/arm64.

However, current main still does not contain the dedicated fix that was tracked separately for this issue, so this should still be considered open pending proper darwin/amd64 verification.

For reference, _demo/go/readdir runs correctly on my current darwin/arm64 host, but that does not prove the original darwin/amd64 problem is gone.

[luoliwoshang]

Yes,fix at #1655 and i will rebase main to check this pr works