builtin println pointer formatting differs from Go

[luoliwoshang]

Summary

println in llgo prints nil pointers as (nil) (via C %p), while Go prints 0x0. This causes test mismatches in TestRunFromTestgo / reader (and similar cases like invoke/struczero/tpmethod).

Repro (example: TestRunFromTestgo / reader)

root@a5b720ceb938:~/llgo/cl/_testgo/reader# go run in.go
hello world (0x0,0x0)
root@a5b720ceb938:~/llgo/cl/_testgo/reader# llgo run in.go
hello world ((nil),(nil))

Expected

hello world (0x0,0x0)

Actual

hello world ((nil),(nil))

Suspected root cause

runtime/internal/runtime/z_print.go uses C fprintf("%p"), which prints (nil) for null pointers on glibc.

Environment

• OS: Linux
• Arch: arm64
• Go toolchain: 1.24.x

[luoliwoshang]

Fixed at #1558