getopt can print a whole bunch of error messages, and when used
standalone (from gnulib) it uses fprintf to do that. But fprintf is a
cancellation point and getopt isn't, and also applying fprintf to a
stream in wide-character mode is not allowed. So every single error
reporting case has an #ifdef _LIBC block in which it calls internal
libc functions instead. The counterpart patch series in glibc makes
it possible to simplify all of that down to a set of #defines at the
top of the file; core code is written as if it is safe to just call
fprintf, flockfile, and funlockfile. (One caveat: it's *not* safe to
call any *other* stdio functions.)
* lib/getopt.c: When _LIBC is defined, define fprintf to
__fxprintf_nocancel, flockfile to _IO_flockfile, and funlockfile
to _IO_funlockfile. When neither _LIBC nor
_POSIX_THREAD_SAFE_FUNCTIONS is defined, define flockfile and
funlockfile as no-ops.
(_getopt_internal_r): Remove all internal #ifdef _LIBC blocks; the
standalone error-printing code can now be used for libc as well.
Add an flockfile/funlockfile pair around one case where the error
message is printed in several chunks. Don't use fputc.