I'm really sorry for replying *that* late, but I had much to do after
I posted here and then forgot totally about this posting. Today I ran
gem update and saw compiling ffi was failing again, which remembered
me of this post. Sorry again.

> Does arch linux split libraries into 'binary' and 'dev' versions like
> Debian?  if so, you'll want to install the 'dev' version of libffi.

No, it doesn't.

> You'll also want to check that libffi is registered properly with pkg-config
> by e.g.  running "pkg-config libffi --cflags"

This says this:
$ pkg-config libffi --cflags
-I/usr/lib/libffi-3.0.9/include

> Have you tried an uninstall/install cycle rather than update?

I did, and it didn't work.

> Does a --user-install work?

No, it doesn't.

All the other C extension gems I'm working with (nokogiri, RedCloth,
etc.) install just fine, so it shouldn't be a bug in mkmf. I even
tried editing mkmf to always make it detect a compilier (by returning
true in have_devel), but then the command failed it couldn't find the
ffi library.

> That's odd as I'm running Arch 32-bit (via VirtualBox on Win7 32-bit) and the ffi-1.0.6 gem builds and installs fine

My other computer runs 64bit Arch Linux and ffi installs fine on it.
On the original computer I can't even reinstall the ffi gem that was
previously installed. I think I'm going to try to build ffi directly
from the sources, bypassing RubyGems...

I really have no clue what's going on here. I appreciate any ideas.

Valete,
Quintus