zlib build problems

[Matthias Dieter Wallnöfer]

Hi ekacnet,

while looking a bit at the buildfarm, I still noticed the Tru64 host 
failing due to zlib 
(http://build.samba.org/?function=View+Build;host=SerNet-Tru64;tree=samba_4_0_test;compiler=cc).
I gave a look at the "lib/zlib/wscript_build" file and saw that there 
seems to be some replacement code for outdated/non-working "zlib"s (as 
the one from Tru64) but obviously it is not always activated.

Are you willing to look into this?

Greets,
Matthias