Remove the shim kernel crate

kernel/src/syscall/setregid.rs

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::SyscallReturn;
+use crate::{prelude::*, process::Gid};
+
+pub fn sys_setregid(rgid: i32, egid: i32, ctx: &Context) -> Result<SyscallReturn> {
+    debug!("rgid = {}, egid = {}", rgid, egid);
+
+    let rgid = if rgid > 0 {
+        Some(Gid::new(rgid as u32))
+    } else {
+        None
+    };
+
+    let egid = if egid > 0 {
+        Some(Gid::new(egid as u32))
+    } else {
+        None
+    };
+
+    let credentials = ctx.posix_thread.credentials_mut();
+    credentials.set_regid(rgid, egid)?;
+
+    Ok(SyscallReturn::Return(0))
+}