devel/liberasurecode: exorcise -Werror more thoroughly

Looks like upstream put a few more in after I took out all of
them in the previous commit. This fixes the build with LLVM 15,
which takes offence in declaring parameterless function as foo()
instead of foo(void).

Approved by: eduardo (mentor)
Differential Revision: https://reviews.freebsd.org/D38524