It's been a while since I've done this (I'm running OpenBSD now, and it turns out that BSC's toolchain tree is a complete mess full of Linux/GNUisms, so I don't even have a working Cell toolchain right now). Basically I downloaded the sources for those libraries, built them, and installed them to the target tree. If memory serves, zlib has a very simple build system; I think I just did something like
and installed libz.a/so/h manually, but you can probably find some information in zlib's Makefile.
as for libiconv, it should support the GNU configure mechanism of specifying
Code:
--target=ppu --prefix=/path/to/target/tree
(where /path/to/target/tree is the directory which contains bin/ , lib/ , include/ et. al. for the PS3 toolchain.
Hope this helps.