zig cc does not support nested @ files: error: unable to parse command line parameters: NestedResponseFile #24386

Zig Version

0.14.1

Steps to Reproduce and Observed Behavior

Files

main.c

#include <stdio.h>

int main() {
    printf("Hello %s\n", ZIG);
    return 0;
}

flags

main.c
@nested-flags
@nested-flags

nested-flags

-DZIG=\"Zig\"

Commands

Working example using Clang 19.1.7

> clang @flags && ./a.out
Hello Zig

Build failure using zig cc

> zig cc @flags
error: unable to parse command line parameters: NestedResponseFile

Expected Behavior

The build should succeed despite the nested @ files.

For context, the error is raised at

This was discovered at meta/buck2#1011. For context, there is some interest in using Zig to build hermetic toolchains using the Buck2 build system. The Buck2 "standard library" (called the prelude) has some support for Zig-based toolchains, but it has started using @ files more extensively as of late. This works fine with Clang and GCC, but breaks with zig cc.