Hi Mark:
The short answer is:
make  check-am
…...
make  check-TESTS
PASS: test-system-cmds
…...
PASS: test-asmobs
PASS: test-ffi
PASS: test-list
……
===================
All 29 tests passed
===================


In more detail the following steps:
Unzipped libffi-3.0.11.tar.gz
Downloaded libffi-3.0.11-includedir-1.patch
Applied that patch
Had to manually apply your diff file patch

(I'll explain in more detail if you wish)

Built and installed libffi in the usual manner.

Then did the same process for guile-2.0.7.tar.gz
did ./configure && make && make check
got the above results.

Here's the summary
Totals for this test run:
passes:                 35268
failures:               0
unexpected passes:      0
expected failures:      6
unresolved test cases:  34
untested test cases:    1
unsupported test cases: 9
errors:                 0

PASS: check-guile


Anything else I can do to help?

Peter