Fixed Curl_gethostname() so that it always returns the un-qualified
machine name rather than being dependent on the socket provider.
Note: The return of getenv("CURL_GETHOSTNAME") is also parsed in case
the developer / test harness provided a fully qualified domain name as
it's value as well.
A shared library tests/libtest/.libs/lihostname.so is preloaded in NTLM
test-cases to override the system implementation of gethostname(). It
makes it possible to test the NTLM authentication for exact match, and
this way test the implementation of MD4 and DES.
If LD_PRELOAD doesn't work, a debug build willl also workk as debug
builds are now made to prefer a specific environment variable and will
then return that content as host name instead of the actual one.
Kamil wrote the bulk of this, Daniel Stenberg polished it.
