feat(zkvms/risc0): Use unstable feature

Author: Syndamia

zkvms/risc0/default.nix

@@ -23,6 +23,12 @@ in zkvmLib.buildPackage craneLib (commonArgs // {
 
   guestTarget = "riscv32im-risc0-zkvm-elf";
 
+  preBuildGuest = ''
+    # Should be set only when RISC0 is compiled with unstable feature
+    # https://github.com/risc0/risc0/blob/b5bf2d4a50cfb954da7f507766ba0f120c716958/risc0/build/src/lib.rs#L430-L435
+    export RISC0_FEATURE_bigint2=""
+  '';
+
   postBuildGuest = ''
     cd ../guest_elf_patch
     cargo run --release

zkvms/risc0/guest/Cargo.toml

@@ -7,7 +7,7 @@ edition = "2021"
 [workspace]
 
 [dependencies]
-risc0-zkvm = { path = "/nix/store/jvl62igv3z8yvayhk1c02hw51adjc0d0-risc0-unstable-2025-03-12/risc0/zkvm", default-features = false, features = ['std'] }
+risc0-zkvm = { path = "/nix/store/jvl62igv3z8yvayhk1c02hw51adjc0d0-risc0-unstable-2025-03-12/risc0/zkvm", default-features = false, features = ['std', 'unstable'] }
 
 wrapper_macro = { version = "0.1.0", path = "../wrapper_macro" }
 

zkvms/risc0/host/Cargo.toml

@@ -4,8 +4,8 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-risc0-zkvm = { path = "/nix/store/jvl62igv3z8yvayhk1c02hw51adjc0d0-risc0-unstable-2025-03-12/risc0/zkvm" }
-risc0-zkp = { path = "/nix/store/jvl62igv3z8yvayhk1c02hw51adjc0d0-risc0-unstable-2025-03-12/risc0/zkp" }
+risc0-zkvm = { path = "/nix/store/jvl62igv3z8yvayhk1c02hw51adjc0d0-risc0-unstable-2025-03-12/risc0/zkvm", features = ['unstable'] }
+risc0-zkp = { path = "/nix/store/jvl62igv3z8yvayhk1c02hw51adjc0d0-risc0-unstable-2025-03-12/risc0/zkp", features = ['unstable'] }
 # https://github.com/risc0/risc0/blob/881e512732eca72849b2d0e263a1242aba3158af/risc0/zkp/Cargo.toml#L23
 hex = { version = "0.4.3", default-features = false, features = ["alloc"] }
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }