option to specify dis(activation) of compiler optimizations.

If option is specified, it will be honored independant of the
--(dis|en)able-debug option.

option to specify dis(activation) of picky compiler warnings.

If option is specified, it will be honored independant of the
--(dis|en)able-debug option.

If option is not specified, it will follow --(dis|en)able-debug
setting, whose default is disabled if not specified.

dereferencing type-punned pointer will break strict-aliasing rules

  gets a 550 response back for the cases where a download (or NOBODY) is
  wanted. It still allows a 550 as response if the SIZE is used as part of an
  upload process (like if resuming an upload is requested and the file isn't
  there before the upload). I also modified the FTP test server and a few test
  cases accordingly to match this modified behavior.

otherwise gethostbyname() is not detected.

  libcurl to somewhat reduce the size of the binary. Run configure
  --disable-proxy.