early stage ldso: remove symbolic references via error handling function

early stage ldso: remove symbolic references via error handling function

while the error handling function should not be reached in stage 2
(assuming ldso itself was linked correctly), this was not statically
determinate from the compiler's perspective, and in theory a compiler
performing LTO could lift the TLS references (errno and other things)
out of the printf-family functions called in a stage where TLS is not
yet initialized.

instead, perform the call via a static-storage, internal-linkage
function pointer which will be set to a no-op function until the stage
where the real error handling function should be reachable.

inspired by commit 63c67053a3e42e9dff788de432f82ff07d4d772a.