It was never really possible to compile a library with one C compiler and expect it to link against code produced by another C compiler, unless both compilers happen to agree on specific ABI details that are either defined outside the C standard or not at all.

And to be honest, this sort of compiler-specific ABI interoperability is a non-problem that doesn't need solving, it's at most relevant for software developers of closed source libraries who distribute the libraries as precompiled blobs. But those must be stamped out for different target-triples anyway.