Nix is a purely functional package manager. It allows multiple versions of a package to be installed side-by-side, ensures that dependency specifications are complete, supports atomic upgrades and rollbacks, allows non-root users to install software, and has many other features. It is the basis of the NixOS Linux distribution, but it can be used equally well under other Unix systems.
smake is a highly portable 'make' program that makes commands up to date based on rules in Makefiles and on the timestamps of the related files. It implements a complete superset of the features of the classical POSIX/Unix make program. It warns about typical misuse of dynamic macros that prevent portability of makefiles. Its automake features allow you to run scripts to automatically create rules for unknown platforms.
BitRock InstallBuilder allows you to create easy-to-use multiplatform installers for Linux (x86/PPC/s390/x86_64/Itanium), Windows, Mac OS X, FreeBSD, OpenBSD, Solaris (x86/Sparc), IRIX, AIX, and HP-UX applications. The generated application installers have a native look-and-feel and no external dependencies, and can be run in GUI, text, and unattended modes. In addition to self-contained installers, the installation tool is also able to generate standalone RPM packages.
stowES (stow Enhancement Script) is a Perl script which tries to ease the use of the "stow" packaging program and software which can be compiled and installed with autoconf. It automates the compilation and installation of software packages and provides some useful functions to maintain your stow packages (e.g., list packages, check packages for integrity, etc.).
Rant is a flexible build tool. The equivalent to a Makefile for make is the Rantfile, which is actually a valid Ruby script that is read in by the rant command. It currently features automated testing, packaging, and RDoc generation for Ruby applications and libraries, creation of gzipped tar and zip archives on all supported platforms without additional software, recognition of file changes based on MD5 checksums, dependency checking for C/C++ source files (makedepend is not required), and more. It can generate a script tailored to the needs of a specific project, which can be used instead of an Rant installation so that users aren't dependent on Rant.