You need wxWidgets 2.8 or newer.
xCHM depends on chmlib.
If you intend to use xCHM as a context-sensitive help tool, you need XMLRPC++.
You can download the xCHM source code here. You can browse it without downloading it here.
I do not make packages for your distribution myself; I only maintain the source code. However packages do exist for some distributions. I do not personally endorse any of these. I cannot guarantee that the packages listed below work or not, and in fact the only thing I will do is remove broken links if you report them. If you want something readily packaged you'll have to take your chances.
xCHM is part of Novell's Cool Tools.
Arch Linux. Debian. Gentoo. FreeBSD. NetBSD. Mint Linux. Solaris. CentOS / RedHat 5.3, by Oliver Niesner. Ubuntu. SuSE. T2 SDE Linux. Fedora.
MacPorts provides xCHM.
If you have made a package for your favourite distribution and you have it available online, let me know and I will add a link to your package here. That way more people who also like your distribution can use xCHM more easily. Thank you.