The 32-bit edition of cmake appears on Haiku Depot Web under the name “CMake” which fails to resolve with pkgman. In fact, this package uses the conventional name “cmake_x86”.
Thats right, because it is the 32bit version.
As already told, for everything wich needs gcc>2 use:
setarch x86
This sets some env vars for the current terminal session (so for the current tab).