[libvirt] FreeBSD and sysconf(_SC_GETPW_R_SIZE_MAX)

On FreeBSD virsh fails to enter interactive mode because vshReadlineInit fails, because virGetUserDirectory fails, because virGetUserEnt fails, because sysconf(_SC_GETPW_R_SIZE_MAX) returns -1 and sets errno to EINVAL. Is this something that gnulib should/could deal with, Eric? Or should we work around it in libvrt and fallback to PATH_MAX when sysconf(_SC_GETPW_R_SIZE_MAX) fails? Matthias