Merge branch 'tg/maint-cache-name-compare' into maint

Even though the index can record pathnames longer than 1<<12 bytes,
in some places we were not comparing them in full, potentially
replacing index entries instead of adding.

* tg/maint-cache-name-compare:
  cache_name_compare(): do not truncate while comparing paths

diff --cc read-cache.c
Simple merge