diff --git a/src/program.rs b/src/program.rs
index b31c4b9..6a5b3d3 100644
--- a/src/program.rs
+++ b/src/program.rs
@@ -28,7 +28,7 @@ use rustix_futex_sync::Mutex;
 /// `mem` should point to the stack as provided by the operating system.
 #[cfg(any(feature = "origin-start", feature = "external-start"))]
 pub(super) unsafe extern "C" fn entry(mem: *mut usize) -> ! {
-    extern "C" {
+    extern "Rust" {
         fn main(argc: c_int, argv: *mut *mut u8, envp: *mut *mut u8) -> c_int;
     }
 
diff --git a/test-crates/external-start/src/main.rs b/test-crates/external-start/src/main.rs
index fac5ca2..32da12c 100644
--- a/test-crates/external-start/src/main.rs
+++ b/test-crates/external-start/src/main.rs
@@ -56,7 +56,7 @@ static EARLY_INIT_ARRAY: unsafe extern "C" fn(i32, *mut *mut u8) = {
 };
 
 #[no_mangle]
-extern "C" fn main(_argc: i32, _argv: *const *const u8) -> i32 {
+fn main(_argc: i32, _argv: *const *const u8) -> i32 {
     eprintln!("Hello from main thread");
 
     at_exit(Box::new(|| eprintln!("Hello from an at_exit handler")));
diff --git a/test-crates/origin-start-no-alloc/src/main.rs b/test-crates/origin-start-no-alloc/src/main.rs
index 8500ec1..f1c91fd 100644
--- a/test-crates/origin-start-no-alloc/src/main.rs
+++ b/test-crates/origin-start-no-alloc/src/main.rs
@@ -21,7 +21,7 @@ fn panic(panic: &core::panic::PanicInfo<'_>) -> ! {
 extern "C" fn eh_personality() {}
 
 #[no_mangle]
-extern "C" fn main(_argc: i32, _argv: *const *const u8) -> i32 {
+fn main(_argc: i32, _argv: *const *const u8) -> i32 {
     eprintln!("Hello!");
 
     // Unlike origin-start, this example can't create threads because origin's
diff --git a/test-crates/origin-start/src/main.rs b/test-crates/origin-start/src/main.rs
index d49c532..7fb3193 100644
--- a/test-crates/origin-start/src/main.rs
+++ b/test-crates/origin-start/src/main.rs
@@ -11,8 +11,8 @@ extern crate compiler_builtins;
 
 use alloc::boxed::Box;
 use atomic_dbg::{dbg, eprintln};
-use origin::thread::*;
 use origin::program::*;
+use origin::thread::*;
 
 #[panic_handler]
 fn panic(panic: &core::panic::PanicInfo<'_>) -> ! {
@@ -27,7 +27,7 @@ extern "C" fn eh_personality() {}
 static GLOBAL_ALLOCATOR: rustix_dlmalloc::GlobalDlmalloc = rustix_dlmalloc::GlobalDlmalloc;
 
 #[no_mangle]
-extern "C" fn main(_argc: i32, _argv: *const *const u8) -> i32 {
+fn main(_argc: i32, _argv: *const *const u8) -> i32 {
     eprintln!("Hello from main thread");
 
     at_exit(Box::new(|| eprintln!("Hello from an at_exit handler")));