The issue is that the libffado scripts assume that they can determine
the host architecture by probing the machine architecture through some
black magic (calling objdump on /bin/mount !). The x32.patch follows
this by reading "uname -m" to determine if it's running on x32 or i386.
The correct solution is to remove all of this code and just invoke
$(CC)
which in Debian package builds should be set to a suitable compiler for
the right architecture. Conveniently, there appears to an option to do
this "DETECT_USERSPACE_ENV=False", so we don't need to patch the source
and we can probably remove x32.patch after this as well (untested
though!).
As a workaround you can use "linux32 pbuilder..." when building the
package to override "uname -m". I know that sbuild already does this
for
you which is probably why none of the buildds suffer from this bug.