gethostname: LGPL -> LGPLv2+

[Jim Meyering]

I'd like to use the gethostname module in libvirt (LGPLv2+),
for use when building for mingw.

Considering the size of the module (trivial, 10-line gethostname function
and minimal gethostname.m4), would anyone object to relaxing its license
from LGPL to LGPLv2+?

This is mainly to avoid gnulib's link-time warning:

  ...: undefined reference to address@hidden'

In this particular case, gethostname is essentially a no-op,
and always returns the empty string, since mingw
has no uname function, and in that case, gethostname's
body reverts to this:

    strcpy (name, "");            /* Hardcode your system name if you want.  */