Fix --all-targets build

src/main.rs

@@ -45,6 +45,7 @@ pub extern "C" fn main(_nargs: libc::c_int, _args: *const *const libc::c_char) -
 	0
 }
 
+#[cfg(not(test))]
 #[panic_handler]
 fn panic(info: &core::panic::PanicInfo) -> ! {
 	let _ = writeln!(libc::stdio::stderr(), "Panic: {}", info);

src/system_alloc.rs

@@ -15,6 +15,7 @@ unsafe impl alloc::alloc::GlobalAlloc for System {
 #[global_allocator]
 static SYSTEM_ALLOC: System = System;
 
+#[cfg(not(test))]
 #[alloc_error_handler]
 fn alloc_error(_: core::alloc::Layout) -> ! {
 	panic!("allocation failure");