How can I be sure a library doesn't use wchar_t

Question

While I worked to link a library on a new platform, I got the following error:

foo.o uses 2-byte wchar_t yet the output is to use 4-byte wchar_t; use of wchar_t values across objects may fail

I searched stackoverflow and found this thread: How to set 2 byte wchar_t output?

I saw the answer there and it is really helpful

You can strip the Tag_ABI_PCS_wchar_t tags from your internal gcc object binaries if you truly believe they're sizeof(wchar_t)-agnostic.

Is there an automatic way I can be sure that the library is sizeof(wchar_t)-agnostic?

Thanks