Okay, this might be working now.

flake.lock

rtree-c/package.yaml

rtree-c/rtree-c.cabal

rtree-c/src/ReduceC.hs

rtree-c/test/cases/typedef.c

rtree-c/test/expected/main/reduction/r.c

rtree-c/test/expected/main/reduction/r1.c

rtree-c/test/expected/typedef/main.c

rtree-c/test/expected/typedef/reduction/r00.c

rtree-c/test/expected/typedef/reduction/r01.c

rtree-c/test/expected/typedef/reduction/r10.c

rtree-c/test/expected/typedef/reduction/r11.c

rtree-c/test/src/ReduceCSpec.hs