fixes warnings with Xcode 14.3 as in previous commit
+ allocate +1 in Log_output buffer - snprintf(MULL, 0...) returns number
of bytes without terminating '\0'. std::string storage isn't guaranteed
to be NULL-terminated (std::string("").at(0) throws an exception). The
buffer is somewhere preallocated 256 which prevents problem but it's
better not to rely upon it.
+ comment out some unused function in LDGM that also triggered the
warning but looked a bit suspicious so it was not clear how to fix
