This was causing a stringop-truncation compiler warning in gcc 8 when
the #defined values being copied from were string literals.
`error: 'strncpy' output truncated before terminating nul copying 8 bytes from a string of the same length [-Werror=stringop-truncation]`
These fields aren't NUL terminated C strings, they are a fixed width buffer
that is supposed to be space (0x20) padded.
