Increase _DW_ENV_STRING_SIZE to 257 bytes, this is the maximum size the utsname fields can be according to the Linux utsname man page. This seems to be a bit excessive but, this will prevent any possible issue on future operating system support. It also eliminates a bogus warning when compiling using gcc 9 and higher, which I believe is this gcc bug: warning: ‘__builtin_strncpy’ output may be truncated copying 64 bytes from a string of length 64 [-Wstringop-truncation] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780