libtiff: add PACKAGECONFIG for libdeflate and zstd

The main reason for this is an issue with latest libtiff update that causes
gtk4-native configure to fail in finding libtiff (while it just builds
fine for target).
By comparing libtiff-4.pc for native and target it turned out, that
it links for native with zstd and libdeflate. Probably because those libs
were found on my host system.

Adding PACKAGECONFIGS for the libs prevents us from taking them from the host.

Signed-off-by: Markus Volk <f_l_k@t-online.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>