std.fs.File.Reader: fix freestanding build failures

This should be enough to unblock people for now. We'll revisit the way
these things are organized with the upcoming std.Io interface.

fixes #24685
e395c24c6dAndrew Kelley committed on 8/15/2025, 6:10:29 AMparent47e6528
1 file changedLine totals unavailable