fix: avoid overflow in linker E2BIG check

Author: weihanglo

compiler/rustc_codegen_ssa/src/back/command.rs

@@ -167,7 +167,10 @@ impl Command {
             //
             // [1]: https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessa
             // [2]: https://devblogs.microsoft.com/oldnewthing/?p=41553
-            let estimated_command_line_len = self.args.iter().map(|a| a.len()).sum::<usize>();
+            let estimated_command_line_len = self
+                .args
+                .iter()
+                .fold(0usize, |acc, a| acc.saturating_add(a.as_encoded_bytes().len()));
             estimated_command_line_len > 1024 * 6
         } else if cfg!(unix) {
             // On Unix the limits can be gargantuan anyway so we're pretty