Make "-O3 -g" the default build flags (again), including for C++ (api/leveldb).
Limit the maximum compression ratio our raw zlib implementation will allow.  Once we have taken 20x the maximum page size, stop.  This prevents pathological behavior in sythetic workloads where a page is forced out of cache, then compresses into a single page on disk, and we repeat for every update.
Limit range in shared cache wtperf configuration.

Avoids using too much disk space.