Pelles C
Pelles C is a complete development kit for Windows and Windows Mobile. It contains among other things an optimizing C compiler, a macro assembler, a linker, a resource compiler, a message compiler, a make utility and install builders for both Windows and Windows Mobile.
OpenSSL a collaborative effort to develop a robust, commercial-grade, full-featured, and Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as a full-strength general purpose cryptography library.