fix(linker): use arg list estimate on only Windows

Though I doubt anyone running rustc outside Unix/Windows

Author: weihanglo

compiler/rustc_codegen_ssa/src/back/command.rs

@@ -139,7 +139,7 @@ impl Command {
 pub(crate)fnvery_likely_to_exceed_some_spawn_limit(&self) -> bool{
 // We mostly only care about Windows in this method, on Unix the limits
 // can be gargantuan anyway so we're pretty unlikely to hit them
-ifcfg!(unix){
+ifcfg!(not(windows)){
 returnfalse;
 }