[exim] Trouble compiling Exim 4.92

Hi list!

I'm trying to compile Exim 4.92, but I get this error:

gcc -o exim
drtables.o: In function `init_lookup_list':
drtables.c:(.text+0x20e): undefined reference to
`spf_lookup_module_info'
collect2: error: ld returned 1 exit status
Makefile:645: recipe for target 'exim' failed
make[1]: *** [exim] Error 1
make[1]: Leaving directory
'/home/download/exim/exim-4.92/build-Linux-x86_64'
Makefile:35: recipe for target 'all' failed
make: *** [all] Error 2

I have these lines in Local/Makefile:

SUPPORT_SPF=yes
CFLAGS += -I/usr/include
LDFLAGS += -L/usr/lib -lspf2

and of course I have libspf2 (and dev...) installed.
I'm using a Debian Jessie.

Any idea?

Thanks
Luca Bertoncello
(lucabert@???)