fix cfg for windows

Author: mustartt

compiler/rustc_metadata/src/creader.rs

@@ -1165,8 +1165,8 @@ fn format_dlopen_err(e: &(dyn std::error::Error + 'static)) -> String {
 }
 
 fn attempt_load_dylib(path: &Path) -> Result<libloading::Library, libloading::Error> {
+    #[cfg(target_os = "aix")]
     if let Some(ext) = path.extension()
-        && cfg!(target_os = "aix")
         && ext.eq("a")
     {
         // On AIX, we ship all libraries as .a big_af archive
@@ -1182,10 +1182,11 @@ fn attempt_load_dylib(path: &Path) -> Result<libloading::Library, libloading::Er
         // flags = RTLD_LAZY | RTLD_LOCAL | RTLD_MEMBER
         // these are not yet in libc https://github.com/rust-lang/libc/pull/4044
         let flags = 0x4 | 0x80000 | 0x40000;
-        unsafe { libloading::os::unix::Library::open(Some(&new_path), flags) }.map(|lib| lib.into())
-    } else {
-        unsafe { libloading::Library::new(&path) }
+        return unsafe { libloading::os::unix::Library::open(Some(&new_path), flags) }
+            .map(|lib| lib.into());
     }
+
+    unsafe { libloading::Library::new(&path) }
 }
 
 // On Windows the compiler would sometimes intermittently fail to open the