Need some Frotz eyes

I’m working at folding in Aldo Cumani’s sfrotz into the main Frotz codebase. Would someone please take a look at the code and help me figure out why the build keeps complaining about
“undefined reference to `f_setup’”, The code in question is in the pre-2.44 branch.

Can’t reproduce:

git checkout pre-2.44

Builds fine :-/
(Linux, tested with GCC 4.5.3 and 4.6.3.)

It’s the sfrotz target that I’m having trouble with.

$ make sfrotz
gcc -o sfrotz src/frotz_common.a src/frotz_sdl.a src/blorblib.a -ljpeg -lpng -lz -lSDL -lSDL_mixer
src/frotz_common.a(main.o): In function `z_piracy':
main.c:(.text+0x7): undefined reference to `f_setup'
src/frotz_common.a(main.o): In function `main':
main.c:(.text+0x27): undefined reference to `os_init_setup'
src/frotz_common.a(process.o): In function `call':
process.c:(.text+0x3ab): undefined reference to `f_setup'
process.c:(.text+0x4c7): undefined reference to `f_setup'
yadda yadda...

Oops, didn’t know there was an sfrotz target. The build doesn’t get that far here though:

src/sdl/sf_images.c: In function 'loadpng': src/sdl/sf_images.c:97:7: error: dereferencing pointer to incomplete type

Smells like a missing #include, but not sure.