Fall back to "-" if the handling has not been decided yet.

Fixes: #950
Fixes: #944
Fixes: #918

utils expect to receive SIGHUP).

Fixes: #947

memlevel 8.

Fix testcases which depend on older values.

gzip_window and gzip_memlevel.

Still same pessimal values though.

Fixes: #876

Thanks to new GCC for spotting those.

The size of a regex is a size_t.  Spotted by gcc 4.6

returns random file names

Eventually, we want to be able to do synthetic everywhere, but for
now, mark it as just available in vcl_error.

Fixes: #936

Record the original strdup-ed value so we can free it afterwards.

Fixes: #935

We were accidentially sending an end-chunk in some cases where a
response was bodyless such as for 304s.

Thanks to Chris Davies for spotting them.

Restrict visibility of symbols to the symbols we actually want to be
public.

This should work around build problems

Also mark vcs_version.h as a maintainer built file, not a
configure-built file.