Diff-ext is an extension for filemanagers such as Windows Explorer and Nautilus that allows to launch diff/merge tools on selected files.
Open source and free source code static analyzer
AdLint is a source code static analyzer. It can point out insecure or nonportable code fragments, and can measure various quality metrics of the source code. It (currently) can analyze source code compliant with ANSI C89 / ISO C90 and partly ISO C99. AdLint is written in Ruby. So, it is available for Windows, Mac OS X, GNU/Linux, FreeBSD and any other platforms supported by Ruby.
Utilities for AdLint the source code static analyzer
AdLint Goodies is a collection of miscellaneous utilities for AdLint. All goodies are written in Ruby and available for Windows, Mac OS X, GNU/Linux, FreeBSD and any other platforms supported by Ruby.