Fix an error in the recursive call in libffi-type-pointer for
foreign-struct-type, now parse the slot-type, which is unparsed.  This
makes FSBV.3 and FSBV.4 succeed.  Removed quote from test FSBV.2; this
makes FSBV.2 succeed.

Ubuntu 11.10 ships with libffi6 and not libff5, so these libraries are
now added to the load list.

Comment referred to "FSBV" now corrected to "libffi".  Other uses (the
tests and foreign library for tests, the *feature* symbol, and the
variable 'fsbvp resulting from fn-call-by-value-p) genuinely refer to
FSBV and not specifically libffi.  Distinction: "FSBV" refers to all
calls of structures by value, whether accomplished with the help of
libffi or not (some compilers have FSBV built in), "libffi" refers to
the use of the libffi library whether or not for calling foreign
structures by value (there are other functions not yet made use of in
CFFI, but someday might).