Merge the already-merged parts of the 0.74 branch.

This is a no-op merge, via 'git merge -s ours', which records that all
the commits up to this point on the 0.74 branch are bug fixes
cherry-picked from master, and don't need merging back to master.

From this point onwards, the 0.74 branch will contain fresh work that
_will_ need merging back to master. This preliminary non-merge allows
me to avoid needless conflicts during that process.

Author: sgtatham