message: Update apply-iwyu tool to report compile errors
  Note: apply-iwyu on a lone .h file *will* fail due to c++/c confusion.
  Cr-Commit-Position: refs/heads/master@{#33525}
diff: @@ -33,11 +33,22 @@ else
  FILE_H=""
  fi
  +# IWYU has a confusing set of exit codes. Discard it.
  iwyu -Xiwyu --no_fwd_decls -D__X86_64__ -DWEBRTC_POSIX -I . \
  -I third_party/abseil-cpp \
  -I third_party/googletest/src/googlemock/include \
  -I third_party/googletest/src/googletest/include \
  - $FILE_CC |& fix_include || echo "Some files modified"
  + $FILE_CC >& /tmp/includefixes$$ || echo "IWYU done, code $?"
  +
  +if grep 'fatal error' /tmp/includefixes$$; then
  + echo "iwyu run failed"
  + cat /tmp/includefixes$$
  + rm /tmp/includefixes$$
  + exit 1
  +else
  + fix_include < /tmp/includefixes$$ || echo "Some files modified"
  + rm /tmp/includefixes$$
  +fi
  if [ $REMOVE_CC_INCLUDES == "yes" ]; then
  if [ -n "$FILE_H" ]; then
  