The repo allows one implementation per export. Move libc's rename into
libc/src/Rename.cpp, compile that file into both libc and libkernel, and
drop the second copy from libkernel's Stdio.cpp. FilesystemError moves to a
header so the shared source can use it.
The test now checks that the symbol it resolves belongs to libkernel (module
handle on Windows, dladdr on Linux) so it fails when the export is removed.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
ps54all