Update from 2.4.7 to 2.4.8.
UPGRADE URGENCY: moderate if you don't experience any of the fixed problems.
* [BUGFIX] Make install now uses cp -f to avoid 'text file busy' errors.
* [BUGFIX] redis-check-aof is now large files safe also on 32 bit systems.
* [BUGFIX] Issue #327 fixed: maxmemory and replication now work much better.
* [BUGFIX] Now HINCRBY can detect overflows too. Fix for issue #330.
* [BUGFIX] Fixed compilation with latest clang.
* [BUGFIX] Fixed handling of empty sorted sets produced in RDB by
very old Redis versions (1.2.x).