abort: fix unsafe-op-in-unsafe-fn, signal path, unused imports

- abort() body: use signal::sys::SIGABRT (the platform-independent name
  the signal module uses for both linux and redox submodules)
- call sites: wrap abort() in unsafe { } blocks (Rust 2024 edition's
  unsafe_op_in_unsafe_fn lint makes this mandatory inside unsafe fns)
- stdlib/mod.rs, start.rs: drop now-unused 'intrinsics' import

src/header/assert/mod.rs

@@ -20,5 +20,5 @@ pub unsafe extern "C" fn __assert_fail(
 
     eprintln!("{}: {}:{}: Assertion `{}` failed.", func, file, line, cond);
 
-    crate::header::stdlib::abort();
+    unsafe { crate::header::stdlib::abort() };
 }

src/header/stdlib/mod.rs

@@ -2,7 +2,7 @@
 //!
 //! See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/stdlib.h.html>.
 
-use core::{convert::TryFrom, intrinsics, iter, mem, ptr, slice};
+use core::{convert::TryFrom, iter, mem, ptr, slice};
 use rand::{
     RngExt, SeedableRng,
     distr::{Alphanumeric, Distribution, Uniform},
@@ -117,8 +117,8 @@ pub unsafe extern "C" fn a64l(s: *const c_char) -> c_long {
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn abort() -> ! {
     log::error!("Abort");
-    crate::header::signal::raise(crate::header::signal::redox::SIGABRT as c_int);
-    _Exit(128 + crate::header::signal::redox::SIGABRT as c_int);
+    crate::header::signal::raise(crate::header::signal::sys::SIGABRT as c_int);
+    _Exit(128 + crate::header::signal::sys::SIGABRT as c_int);
 }
 
 #[cfg(not(target_pointer_width = "64"))]

src/lib.rs

@@ -69,7 +69,7 @@ pub extern "C" fn relibc_panic(pi: &::core::panic::PanicInfo) -> ! {
     let mut w = platform::FileWriter::new(2);
     let _ = w.write_fmt(format_args!("RELIBC PANIC: {}\n", pi));
 
-    crate::header::stdlib::abort();
+    unsafe { crate::header::stdlib::abort() };
 }
 
 #[cfg(not(test))]
@@ -100,7 +100,7 @@ pub extern "C" fn rust_oom(layout: ::core::alloc::Layout) -> ! {
         layout.align()
     ));
 
-    crate::header::stdlib::abort();
+    unsafe { crate::header::stdlib::abort() };
 }
 
 #[cfg(not(test))]
@@ -113,5 +113,5 @@ pub extern "C" fn _Unwind_Resume() -> ! {
     let mut w = platform::FileWriter::new(2);
     let _ = w.write_str("_Unwind_Resume\n");
 
-    crate::header::stdlib::abort();
+    unsafe { crate::header::stdlib::abort() };
 }

src/start.rs

@@ -1,7 +1,7 @@
 //! Startup code.
 
 use alloc::{boxed::Box, vec::Vec};
-use core::{intrinsics, ptr};
+use core::ptr;
 
 #[cfg(target_os = "redox")]
 use generic_rt::ExpectTlsFree;
@@ -78,7 +78,7 @@ unsafe fn copy_string_array(array: *const *const c_char, len: usize) -> Vec<*mut
 #[unsafe(no_mangle)]
 pub unsafe fn relibc_verify_host() {
     if !Sys::verify() {
-        stdlib::abort();
+        unsafe { stdlib::abort() };
     }
 }
 #[unsafe(link_section = ".init_array")]