AC_CHECK_HEADERS([ sys/acl.h sys/libacl.h sys/types.h unistd.h ])
# We need openat() with O_NOFOLLOW from POSIX-2008. Without them, we
AC_CHECK_HEADERS([ sys/acl.h sys/libacl.h sys/types.h unistd.h ])
# We need openat() with O_NOFOLLOW from POSIX-2008. Without them, we