bash 4.2 breaks source finding libs in lib/filename...

[Linda Walsh]

I have several files that source the lib files by expecting
the name of the lib to be checked against PATH --

but this no longer works when the library is in lib/filename.

How can one get the same behavior as before and look up files
relative to PATH regardless of them having a '/' in them?

Why was this functionality removed in non-posix mode?

I could even live with it not working in restricted bash, where I could
see it might be a security risk, but in standard scripts?