build breakage - redhat complains about memLow/HighWat casting

See...

http://builds.hq.northscale.net:8010/builders/wallace_redhate_64/builds/425/steps/compile/logs/stdio

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make[2]: Entering directory `/home/buildbot/redhate_64/wallace_redhate_64/wallace/components/tmp/repo_ep-engine/ep-engine'
cd . && /bin/sh ./config.status config.h
config.status: creating config.h
config.status: config.h is unchanged
CXX ep_la-dispatcher.lo
CXX ep_la-ep.lo
cc1plus: warnings being treated as errors
ep_engine.h: In member function ‘ENGINE_ERROR_CODE EventuallyPersistentEngine::initialize(const char*)’:
ep_engine.h:630: warning: converting to ‘size_t’ from ‘double’
ep_engine.h:633: warning: converting to ‘size_t’ from ‘double’
make[2]: Leaving directory `/home/buildbot/redhate_64/wallace_redhate_64/wallace/components/tmp/repo_ep-engine/ep-engine'
make[2]: *** [ep_la-ep.lo] Error 1
make[1]: Leaving directory `/home/buildbot/redhate_64/wallace_redhate_64/wallace/components/tmp/repo_ep-engine/ep-engine'
make[1]: *** [all] Error 2
rake aborted!
ERROR: cmd failed: make
ERROR: with result: false, 512