Update src/bootstrap/src/lib.rs

Co-authored-by: Urgau <3616612+Urgau@users.noreply.github.com>

Author: SchmErik

src/bootstrap/src/lib.rs

@@ -100,6 +100,7 @@ const EXTRA_CHECK_CFGS: &[(Option<Mode>, &str, Option<&[&'static str]>)] = &[
     // (Some(Mode::Std), "target_os", Some(&[])),
     // #[cfg(bootstrap)] zkvm
     (Some(Mode::Std), "target_os", Some(&["zkvm"])),
+    // #[cfg(bootstrap)] risc0
     (Some(Mode::Std), "target_vendor", Some(&["risc0"])),
     (Some(Mode::Std), "target_arch", Some(&["asmjs", "spirv", "nvptx", "xtensa"])),
     /* Extra names used by dependencies */