diff --git a/lib/std/Thread.zig b/lib/std/Thread.zig
index 5bfaef6127..25261053ee 100644
--- a/lib/std/Thread.zig
+++ b/lib/std/Thread.zig
@@ -280,12 +280,13 @@ pub fn getCurrentId() Id {
 pub const CpuCountError = error{
     PermissionDenied,
     SystemResources,
+    Unsupported,
     Unexpected,
 };
 
 /// Returns the platforms view on the number of logical CPU cores available.
 pub fn getCpuCount() CpuCountError!usize {
-    return Impl.getCpuCount();
+    return try Impl.getCpuCount();
 }
 
 /// Configuration options for hints on how to spawn threads.
@@ -782,6 +783,10 @@ const WasiThreadImpl = struct {
         return tls_thread_id;
     }
 
+    fn getCpuCount() error{Unsupported}!noreturn {
+        return error.Unsupported;
+    }
+
     fn getHandle(self: Impl) ThreadHandle {
         return self.thread.tid.load(.seq_cst);
     }
diff --git a/src/link.zig b/src/link.zig
index f407ad2f4c..03ee3185ab 100644
--- a/src/link.zig
+++ b/src/link.zig
@@ -538,7 +538,7 @@ pub const File = struct {
     pub fn flush(base: *File, arena: Allocator, tid: Zcu.PerThread.Id, prog_node: std.Progress.Node) FlushError!void {
         if (build_options.only_c) {
             assert(base.tag == .c);
-            return @as(*C, @fieldParentPtr("base", base)).flush(arena, prog_node);
+            return @as(*C, @fieldParentPtr("base", base)).flush(arena, tid, prog_node);
         }
         const comp = base.comp;
         if (comp.clang_preprocessor_mode == .yes or comp.clang_preprocessor_mode == .pch) {