Log Message:
libffcall: update to 2.2.

New in 2.2:

* Added support for the following platforms:
  (Previously, a build on these platforms failed.)
  - armv6 (Raspberry Pi): Linux.
  - hppa: Linux 32-bit.
  - riscv32: Linux with ilp32d ABI.
  - riscv64: Linux with lp64d ABI.

* The build for the mips 32-bit ABI is now compatible with toolchains for
  the 'fpxx' ABI variant.  The downside is that the mips1 architecture is
  no longer supported.

* Fixed a bug regarding passing of more than 8 arguments on the following
  platforms:
  - arm64: Linux 64-bit.

* Fixed a stack corruption bug on the following platforms:
  - hppa: HP-UX 32-bit.