[exim] Compiling SPF

Trying to compile SPF support and there seems to be two sets of
instructions. The wiki says:

EXPERIMENTAL_SPF=yes
CFLAGS=-DSPF -I/usr/local/include
EXTRALIBS_EXIM=-L/usr/local/lib -lspf2

But the EDITME file contains:

# EXPERIMENTAL_SPF=yes
# CFLAGS += -I/usr/local/include
# LDFLAGS += -lspf2

I'm getting this error:

./exim: error while loading shared libraries: libspf2.so.2: cannot open
shared object file: No such file or directory

That file is in the /usr/lib directory. What am I missing? Thanks in
advance.