This happens when testing the next version of llvm: https://bugs.chromium.org/p/chromium/issues/detail?id=800984

For daisy (arm), dev-libs/libffi build fails with new warnings and errors.

The new warnings are from [-Wunused-result].
Here is one example:
../libffi-3.1/src/closures.c:460:7: warning: ignoring return value of function declared with 'warn_unused_result' attribute [-Wunused-result]
      ftruncate (execfd, offset);
      ^~~~~~~~~  ~~~~~~~~~~~~~~


The new errors are from unrecognized instructions in assembly files.
Here are a couple of examples:
/build/daisy/tmp/portage/dev-libs/libffi-3.1-r4/work/libffi-3.1/src/arm/sysv.S:363:2: error: invalid instruction, did you mean: fldmiax?
 fldmiadgt ip, {d0-d7}
 ^
/build/daisy/tmp/portage/dev-libs/libffi-3.1-r4/work/libffi-3.1/src/arm/sysv.S:412:2: error: invalid instruction, did you mean: fstmiax?
 fstmiadeq r2, {d0-d3}
 ^