openfst fails to cross build from source for two reasons. One is that it
has an unskippable AC_RUN_IFELSE check. Reading configure.ac reveals
that this is a safety check that is also being done in the test suite.
We have no chance of running this test in a cross build so the only
option is to skip it in cross builds. The other is that debian/rules
passes sse flags whenever building on x86, but it should only pass the
flags when building for x86. I'm attaching a patch to fix both for your
convenience.

Helmut