+/* Native Windows API. Which primitive to choose?
+ - gethostname() requires linking with -lws2_32.
+ - GetComputerName() does not return the right kind of hostname.
+ - GetComputerNameEx(ComputerNameDnsHostname,...) returns the right hostname,
+ but it is hard to use portably:
+ - It requires defining _WIN32_WINNT to at least 0x0500.
+ - With mingw, it also requires
+ "#define GetComputerNameEx GetComputerNameExA".
+ - With older versions of mingw, none of the declarations are present at
+ all, not even of the enum value ComputerNameDnsHostname.
+ So we use gethostname(). Linking with -lws2_32 is the least evil. */