The Crossplex package of make macros simplifies the creation of embedded systems, and is powerful enough for large organizations to use for developing elaborate product lines. It allows you to organize many different products under a logical structure, making systems of any complexity easy to specify. When you have many different target platforms, each with multiple different software configurations, Crossplex keeps those configurations from stepping on each other, without requiring redundancy in your source tree. Crossplex allows you to use a single dependency tree encompassing both in-house software and third-party packages, and it is particularly suited to build automation. Crossplex makes it easy to shield your build from the host environment, setting all shell variables explicitly, and giving you complete control over the path that is used at any point in the build. This is nice when you want to support building on a variety of development platforms. Crossplex scales to your needs. You can dabble in the unpacking and patching features as you need them, or you can base your entire system from the ground up on the Crossplex framework. Crossplex supports creation and use of glibc and uClibc toolchains.
uevalrun is a self-contained computation sandbox for Linux, using User-mode Linux for both compilation and execution of the program to be sandboxed. The program can be written in C, C++, Python, Ruby, Perl, or PHP. uevanrun enforces memory limits, timeouts, and output size limits in the sandbox. The primary use case for uevalrun is evaluation of solution programs submitted by contestants of programming contests: uevalrun compiles the solution, runs it with the test input, compares its output against the expected output, and writes a status report.
Lilblue Linux is a Gentoo-based, security-enhanced, fully featured XFCE4 desktop system for amd64, built on uClibc. Its userland utilities are not provided by busybox, but by coreutils, util-Linux, etc. It resembles a common Linux system with one exception: It uses uClibc as its standard C library and not the more common glibc, and so brings in some of the advantages of embedded systems. Security enhancements come from Gentoo's hardened toolchain and Grsec/PaX-patched kernel. The fully-featured XFCE4 desktop has software for browsing, email, word processing, multimedia, chat, games, and more.