The various other headers include windows.h and the winsock headers
which give an error when SOCKET and socklen_t are already defined.

Needed for the IPv6 stuff.

These check for optional modules.

TightPNG replaces the ZLIB stuff int Tight encoding with PNG. It still
uses JPEG rects as well. Theoretically, we could build TightPNG with only
libpng and libjpeg - without zlib - but libpng depends on zlib, so this is
kinda moot.

This also fixes a compiler warning.

Conflicts, resolved manually:
	AUTHORS

Original thread: http://sourceforge.net/tracker/?func=detail&aid=3310255&group_id=32584&atid=405860

LibVNCClient: Remove all those WITH_CLIENT_TLS #ifdefs and move GnuTLS specific functionality into tls_gnutls.c.

Bugfixes and support for tight encoding with zlib.

Note that the memory leak was only occurring with the colorspace
emulation code, which is only active when using regular libjpeg (not
libjpeg-turbo.)

Diagnosed by Christian Beier, using valgrind.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>