CIL is a frontend for the C programming language which facilitates program analysis and transformation. CIL will parse and typecheck a program, and compile it into a simplified subset of C. For example, in CIL, all looping constructs are given a single form and expressions have no side effects. This reduces the number of cases which must be considered when manipulating a C program. CIL has been used for a variety of projects, including CCured, a tool which makes C programs memory safe. It supports ANSI C, as well as most of the extensions of the GNU C and Microsoft C compilers. A Perl script acts as a drop-in replacement for either gcc or Microsoft's cl, and allows merging of the source files in your project. Other features include support for control-flow and points-to analyses.
SabreDAV allows you to easily integrate your existing Web application with WebDAV. It supports most of the common clients, including the Mac OS X Finder, the Windows XP/Vista Explorer, DavFS2, Cadaver, NetDrive, and WebDrive. It supports class 1, 2, and 3 WebDAV servers. It implements RFC2518 and revisions from RFC4918. It also implements RFC2617 (Basic/Digest auth).
Nuttx is a real-time embedded operating system (RTOS). It has a small footprint that is usable in micro-controller environments. It is fully scalable from tiny (8-bit) to moderate embedded (32-bit) systems. It also aims to be fully compliant to standards, to be fully real time, and to be totally open.
Unifdef is useful for removing #ifdef'ed lines from a file while otherwise leaving the file alone. You specify which symbols are defined or undefined with -D and -U flags, and unifdef removes the corresponding ifdefs, and the enclosed code if appropriate. It's especially useful for removing those "#ifdef BROKEN" and "#ifdef PRIVATE" clauses from code before you release it. Unifdef acts on #if, #ifdef, #ifndef, #elif, #else, and #endif lines, and it knows only enough about C and C++ to know when one of these is inactive because it is inside a comment or a single or double quote.
Botan is a crypto library written in C++. It provides a variety of cryptographic algorithms, including common ones such as AES, MD5, SHA, HMAC, RSA, Diffie-Hellman, DSA, and ECDSA, as well as many others that are more obscure or specialized. It also offers SSL/TLS (client and server), X.509v3 certificates and CRLs, and PKCS #10 certificate requests. A message processing system that uses a filter/pipeline metaphor allows for many common cryptographic tasks to be completed with just a few lines of code. Assembly and SIMD optimizations for common CPUs offers speedups for critical algorithms like AES and SHA-1.