ptsname_r: Work around bug on Android 4.3. * m4/ptsname_r.m4 (gl_FUNC_PTSNAME_R): Define HAVE_ESSENTIALLY_WORKING_PTSNAME_R. Test whether the return value is correct. * lib/ptsname_r.c (__ptsname_r): If HAVE_ESSENTIALLY_WORKING_PTSNAME_R is defined, just fix the return value. * doc/glibc-functions/ptsname_r.texi: Mention the Android bug. Reword: The behaviour of musl libc is nothing to be "fixed", since it is compliant with the next POSIX standard.

#include <stddef.h>
int xmemcoll (char *, size_t, char *, size_t);
int xmemcoll0 (char const *, size_t, char const *, size_t);