Possible Duplicate:
Good STL-like library for C
Are there any open source C libraries with common data structures?
The Apache Commons project has always struck me as being the library of all things that were forgotten in the Java language. Nowadays I almost always include it by default as a dependency on all new projects.
Is there an equivalent of such an essential, must-have, have-it-all library for the C programming language? (And I really mean C---not C++).