From 00a39efd722308e888a56e0ebb28ef64ec660077 Mon Sep 17 00:00:00 2001
From: r4bbit <445106+0x-r4bbit@users.noreply.github.com>
Date: Wed, 29 Apr 2026 09:45:53 +0200
Subject: [PATCH] chore: fix RISC-V guest build on macOS 26

Add .cargo/config.toml setting CFLAGS_riscv32im_risc0_zkvm_elf to
"-march=rv32im -nostdlib". This prevents cc-rs from injecting
macOS-specific flags (-arch arm64, -mmacosx-version-min) into the
riscv32-unknown-elf-gcc cross-compiler when building C dependencies
(e.g. ring) for the guest target, which causes build failures on
macOS 26 Tahoe.
---
 .cargo/config.toml | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .cargo/config.toml

diff --git a/.cargo/config.toml b/.cargo/config.toml
new file mode 100644
index 0000000..7e43eef
--- /dev/null
+++ b/.cargo/config.toml
@@ -0,0 +1,5 @@
+[env]
+# Prevent cc-rs from injecting macOS-specific flags (e.g. -arch arm64, -mmacosx-version-min)
+# into the RISC-V cross-compiler when building C dependencies (e.g. ring) for the guest target.
+# Without this, builds fail on macOS 26+ with the risc0 C++ toolchain.
+CFLAGS_riscv32im_risc0_zkvm_elf = "-march=rv32im -nostdlib"