Unitag is a language-independent Unicode-based part-of-speech tagging system. Written entirely in ANSI-compatible C, it should (in theory) compile on any OS, but has been tested on 32-bit Windows.
CLISP is a portable ANSI Common Lisp implementation and development environment by Bruno Haible. Interpreter, compiler, debugger, CLOS, MOP, FFI, Unicode, sockets, CLX. UI in English, German, French, Spanish, Dutch, Russian, and Danish.
Tiny library written in C++/wxWidgets designed to manage mathematical objects : parser of expressions, plots, matrixes and complex numbers. Ansi and Unicode are supported. Documentation and rich samples are provided. Compiles with MSVC, BCC, GCC and Clang. Now on Git.