necessary to compile with _THREAD_SAFE defined. This means that people
will get thread-aware code whether they like it or not. This change
is required to allow a process to link against libpthread and libc
to use kernel threads (and prevent each thread from clobbering another
thread's errno just be doing a syscall).
This is bound to break some ports, but it is strictly allowed by ANSI C,
so anything that breaks as a result was already broken anyway 8-).
"Sorry".