string: Add strerrorname and strerrordescazanella/sig_err-improvements

The strerrorname returns error number name (i.g. "EINVAL" for EINVAL)
while strerrordesc returns string describing error number (i.g
"Invalid argument" for EINVAL).  Different than strerror, strerrordesc
does not attempt to translate the return description and both functions
return NULL for an invalid error number.

They should be used instead of sys_errlist and sys_nerr and both are
thread and async-signal safe.  These functions are GNU extensions.

Checked on x86-64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
and s390x-linux-gnu.

0 files changed, 0 insertions, 0 deletions