libffi errors with --enable-debugging-features

Hi,

I have this problem with the libffi available in Gentoo's portage and 
with the standalone libffi-2.1 as supplied by Greg on x86_64:

$ make
...
In file included from libsablevm.c:18:
/home/research/ccl/cpicke/include/ffi.h:191: warning: function 
declaration isn't a prototype
/home/research/ccl/cpicke/include/ffi.h:204: warning: function 
declaration isn't a prototype
/home/research/ccl/cpicke/include/ffi.h:273: warning: function 
declaration isn't a prototype
make[5]: *** [libsablevm.lo] Error 1
make[5]: Leaving directory 
`/home/research/ccl/cpicke/sablevm-verbose_methods/src/libsablevm'
make[4]: *** [all-recursive] Error 1
make[4]: Leaving directory 
`/home/research/ccl/cpicke/sablevm-verbose_methods/src/libsablevm'
make[3]: *** [all] Error 2
make[3]: Leaving directory 
`/home/research/ccl/cpicke/sablevm-verbose_methods/src/libsablevm'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory 
`/home/research/ccl/cpicke/sablevm-verbose_methods/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory 
`/home/research/ccl/cpicke/sablevm-verbose_methods'
make: *** [all] Error 2

It only happens when I use --enable-debugging-features.

Any clues as to how we can fix this?  Maybe some too strict checks were 
introduced recently.  You can check out the problem by trying to build 
on magic.cs.mcgill.ca

Cheers,
Chris