_tx_error needs to preserve the errno value it is supposed to display
lib - userland libraries
Fix is attached. Still need review.
_tx_error, called by t_error, is supposed to display a message,
followed by the error string for the error defined in t_errno,
followed by the error string for the error defined in errno. If any
of the system calls/library routines invoked between the start of
_tx_error and when it calls perror() set errno, the output will be