rts/linker: Catch archives masquerading as object files

Check the file's header to catch static archive bearing the `.o`
extension, as may happen on Windows after the Clang refactoring.

See #21068

1 files changed, 10 insertions, 1 deletions

diff --git a/rts/Linker.c b/rts/Linker.c
index a98f0bd2cb..88734bd597 100644
--- a/rts/Linker.c
+++ b/rts/Linker.c
@@ -1356,7 +1356,7 @@ preloadObjectFile (pathchar *path)
 
    image = stgMallocBytes(fileSize, "loadObj(image)");
 
-#endif
+#endif /* !defined(darwin_HOST_OS) */
 
    int n;
    n = fread ( image, 1, fileSize, f );
@@ -1401,6 +1401,15 @@ static HsInt loadObj_ (pathchar *path)
        return 1; // success
    }
 
+   if (isArchive(path)) {
+       if (loadArchive_(path)) {
+            return 1; // success
+       } else {
+            IF_DEBUG(linker,
+                        debugBelch("tried and failed to load %" PATH_FMT " as an archive\n", path));
+       }
+   }
+
    ObjectCode *oc = preloadObjectFile(path);
    if (oc == NULL) return 0;