I have a prototype of basic rust support in src/libjeffpc-rust-extra as well as a urldecode implementation.

The annoying thing is, there are 3 choices:

1. don't use rust, keep libjeffpc pure C
2. require rust, implement code in C or rust depending on what makes more sense
3. use rust if available

The third option has two sub-options:

1. implement everything in C, and some things in rust (all API functions are available everywhere)
2. implement some things in C and some in rust (some API functions are not available in non-rust environments)

Perhaps as an experiment, option 3.2 is the way to go. If there is any issue with rust and it needs to be ripped out, it isn't much wasted effort.