fnkdat is a C header and source file that may be statically linked to a binary. It provides a platform independent interface for determining common directory names (e.g. "user directory", "config directory", etc...). It's particularly well suited for games, but by no means limited to that use.
XParam is an extensible, type-safe, non-intrusive, object-oriented tool for general-purpose object serialization and deserialization in C++, good for parsing command-line parameters and cross-program/cross-platform communication. It can handle named parameters as well as object streams. It recognizes class hierarchies, abstract interfaces, and polymorphism, and can therefore serve as a plug-in management framework (e.g., for strategy management).