try to normalize whitespace across platforms

otherwise, it will get trimmed if the linker is recognized (and `for_each` is invoked), but not otherwise.

compiler/rustc_codegen_ssa/src/back/link.rs

diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index 1e5066b..a5b3df6 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -825,10 +825,10 @@ fn for_each(bytes: &[u8], mut f: impl FnMut(&str, &mut String)) -> String {
             .strip_prefix("Warning: ")
             .unwrap_or(&escaped_stderr)
             .replace(": warning: ", ": ");
-        lint_msg(format!("linker stderr: {escaped_stderr}"));
+        lint_msg(format!("linker stderr: {}", escaped_stderr.trim_end()));
     }
     if !escaped_stdout.is_empty() {
-        lint_msg(format!("linker stdout: {}", escaped_stdout))
+        lint_msg(format!("linker stdout: {}", escaped_stdout.trim_end()))
     }
     if !linker_info.is_empty() {
         lint_info(linker_info);