Rollup merge of #91504 - cynecx:used_retain, r=nikic

`#[used(linker)]` attribute

See https://github.com/dtolnay/linkme/issues/41#issuecomment-927255631.

compiler/rustc_span/src/symbol.rs

@@ -449,6 +449,7 @@ symbols! {
         compare_exchange_weak,
         compile_error,
         compile_error_macro,
+        compiler,
         compiler_builtins,
         compiler_fence,
         concat,
@@ -818,6 +819,7 @@ symbols! {
         link_ordinal,
         link_section,
         linkage,
+        linker,
         lint_reasons,
         literal,
         load,
@@ -1466,6 +1468,7 @@ symbols! {
         use_extern_macros,
         use_nested_groups,
         used,
+        used_with_arg,
         usize,
         v1,
         va_arg,