function executed by resume_with() has to return a continuation

Merge branch 'develop'

Fix various syntax errors caused by merging+edits.

Just clobber master version with develop version as the master had issues caused by whatever merge was done on this earlier. And then not truly fixed by further edits.

Merge branch 'develop'

Merge branch 'develop'

Merge branch 'develop'

Merge branch 'develop'

Merge branch 'develop'

Revert "build: apply defect macro tests"

This reverts commit f8c1f30.

boost.context must still build for boost.coroutine

Merge branch 'master' of github.com:boostorg/context