GCC + any text editor such as VIM is a very light alternative.
For Windows Development, all you need is inside MinGW
Edit: If you are in dire need of an IDE you can also use the MinGW tools from Eclipse with the CDT plugin. Although it adds weight to the solution because of the installation of Eclipse, this is what I really use to build my small DLLs (JNI wrappers in my case).
You can setup your small and direct makefiles or let Eclipse do it automatically for you and concentrate only on the source files (*.h, *.c).
The best part of using this approach instead other IDE is that you do not need Eclipse to further build the DLL, since the underlying project files generated are standard ones directly usable by integrated dev inside MinGW (or any Unix distro) such as make, configure, automake, and so on.