U++ is a C++ cross-platform rapid application development suite focused on programmers' productivity without sacrificing runtime performance. Based on strictly deterministic design, it provides a viable alternative to garbage-collected platforms, even for business logic oriented problems.
pyPEG is a quick and easy solution for creating a parser in Python programs. pyPEG uses a PEG language in Python data structures to parse, so it can be used dynamically to parse nearly every context free language. The output is a plain Python data structure called pyAST, or, as an alternative, XML.
crosstool-NG is a versatile toolchain generator, aiming at being highly configurable. It supports multiple target architectures, different components (glibc/uClibc...) and versions. crosstool-NG also features debugging utilities (DUMA, strace...) and generation tools (sstrip...).
cparser is a recursive descent C99 parser written in C99. It contains a lexer, parser, constructs an AST, and does semantic analysis. It is currently used as a frontend to the libFirm intermediate representation, but can be used independently. It supports lots of GNU extensions: enough to parse Linux/BSD system headers and compile typical C projects with it. It is able to bootstrap itself, and compiles and runs the spec CINT2000 without problems.