It's a shame we never got a package manager for C (or C++).

EDIT: perhaps I should have been clearer; by not having one early on, we now have multiple competing package managers, with no clear winner. Responses prove that point.

I worked at a shop where we used Boost in a C++ code base that the only use of C++ was the harness to use Boost. After that, it was all C, object-styled C, as that code base started before C++ compilers were not a template overlay on C.