Most large-scale FOSS projects in C I've seen tend to be structured in OO-like ways. The C language actually lends itself well to a low-level, Nygaard-style OO

Most large-scale FOSS projects in C I've seen tend to be structured in OO-like ways. The C language actually lends itself well to a low-level, Nygaard-style OO when you reach a certain scale and complexity across modules. Though, if your project is more of a toolkit, then a strictly procedural style is probably better.