Currently the number of header files passed to jextract is restricted to 1. If a library consists of multiple header files, a user has to create a new header file that includes all the library header files, and then pass this new header file to jextract.

Jextract could do this automatically as well, and the implementation still has some leftover code to do this. (It seems to have been disabled initially for the sake of simplicity, while we were prototyping the tool).