strerrorname_np: New module. * lib/string.in.h (strerrorname_np): New declaration. * lib/strerrorname_np.c: New file. * m4/strerrorname_np.m4: New file. * m4/string_h.m4 (gl_HEADER_STRING_H_BODY): Test whether strerrorname_np is declared. (gl_HEADER_STRING_H_DEFAULTS): Initialize GNULIB_STRERRORNAME_NP, HAVE_STRERRORNAME_NP, REPLACE_STRERRORNAME_NP. * modules/string (Makefile.am): Substitute GNULIB_STRERRORNAME_NP, HAVE_STRERRORNAME_NP, REPLACE_STRERRORNAME_NP. * modules/strerrorname_np: New file. * tests/test-string-c++.cc: Verify the signature of strerrorname_np. * doc/glibc-functions/strerrorname_np.texi: Mention the new module and the glibc 2.32 bug.