Change main from extern "C" to extern "Rust".

This function is called from Rust code, so it doesn't need to be
`extern "C"`.

Author: puppymati

example-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")));

example-crates/origin-start-lto/src/main.rs

@@ -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")));

example-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

example-crates/origin-start/src/main.rs

@@ -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")));

example-crates/tiny/src/main.rs

@@ -18,6 +18,6 @@ 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 {
     42
 }

src/program.rs

@@ -116,7 +116,7 @@ unsafe fn init_runtime(mem: *mut usize, envp: *mut *mut u8) {
 #[cfg(any(feature = "origin-start", feature = "external-start"))]
 #[allow(unused_variables)]
 unsafe fn call_user_code(argc: c_int, argv: *mut *mut u8, envp: *mut *mut u8) -> i32 {
-    extern "C" {
+    extern "Rust" {
         fn main(argc: c_int, argv: *mut *mut u8, envp: *mut *mut u8) -> c_int;
     }