Allow pylibmc to be disabled.
Allow pylibmc to be disabled.

ywarezk/heroku-buildpack-geodjango,samuelhavron/heroku-buildpack-python,samuelhavron/heroku-buildpack-python,brianthomas/heroku-buildpack-textmining,thenovices/heroku-buildpack-scipy,dbrgn/heroku-buildpack-python-sklearn,kennethjiang/heroku-buildpack-python-libffi,SciDevs/heroku-buildpack-python-scikit-learn-git,kikin81/heroku-buildpack,pkumar-appd/python-buildpack,samuelhavron/heroku-buildpack-python,julienbou/heroku-buildpack-serpan,manufacturedba/heroku-buildpack-python,projetoeureka/heroku-buildpack-scipy,benmurden/heroku-buildpack-python-ember,osharim/-heroku-buildpack-python,dbrgn/heroku-npscipy,Gliimpse/heroku-buildpack-SWIG-python,benjaminfox/heroku-buildpack-python-geoip,icoxfog417/heroku-buildpack-python,osharim/-heroku-buildpack-python,samuelhavron/heroku-buildpack-python,Tiger66639/buildbot-master-buildpack,kikin81/heroku-buildpack,benmurden/heroku-buildpack-python-ember,jimlindeman/python-buildpack-collectd,scrapinghub/scrapinghub-buildpack-scrapy,kennethjiang/heroku-buildpack-python-libffi,film42/heroku-buildpack-python-wkhtmltopdf,driftyco/heroku-buildpack-sphinx,jms6520/cf-python,Nazanin84/python-buildpack,orablu/heroku-buildpack,cloudfoundry/python-buildpack,integricho/heroku-buildpack-python-ffmpeg2.1-with-codecs,mfenniak/heroku-buildpack-python-libffi,beni55/heroku-buildpack-python,jimlindeman/python-buildpack-collectd,gitricko/apt-python-buildpack,edenspiekermann-amsterdam/heroku-buildpack-python,everysignalinc/heroku-buildpack-python-scikit-learn-git,lyft/heroku-buildpack-python-data,nikita-pivovarov/heroku-buildpack-python-ldap,nemesiscodex/heroku-buildpack-python,zakdoek/heroku-buildpack-django,cloudfoundry/python-buildpack,grivescorbett/heroku-buildpack-python,apiaryio/heroku-buildpack-python-scons,jamarparris/heroku-buildpack-python-swig,markine/heroku-buildpack-python,psrthegreat/heroku-buildpack-python-sklearn,gitricko/apt-python-buildpack,ad-m/heroku-buildpack-python,drinks/heroku-buildpack-python-scipy,wbrefvem/heroku-buildpack-python,predata/heroku-buildpack-scipy,samuelhavron/heroku-buildpack-python,cloudfoundry/python-buildpack,ryanhiebert/heroku-buildpack-python,wbrefvem/heroku-buildpack-python,everysignalinc/heroku-buildpack-python-scikit-learn-git,maxcountryman/heroku-buildpack-python,rollokb/heroku-buildpack-python,Gliimpse/heroku-buildpack-SWIG-python,miraculixx/heroku-buildpack-python,mfenniak/heroku-buildpack-python-libffi,swils/heroku-buildpack-python,cclauss/heroku-buildpack-python,marcospy/hackathon-globo-app,mobify/heroku-buildpack-python-swig,dbrgn/heroku-npscipy,junyoed/heroku-buildpack-python,igroff/heroku-buildpack-python,doda/heroku-buildpack-python,marcospy/hackathon-globo-app,jms6520/cf-python,soapril/heroku-buildpack-python,18F/python-buildpack,nadirizr/heroku-buildpack-python-gulp,drinks/heroku-buildpack-python-scipy,SciDevs/heroku-buildpack-python-scikit-learn-git,cirlabs/heroku-buildpack-geodjango,AltSchool/heroku-buildpack-python,nwkotto/geodjango-buildpack-with-geos,ekkleesia2/heroku-buildpack-python,SciDevs/heroku-buildpack-python-scikit-learn-git,kowito/python-buildpack,ianyh/heroku-buildpack-python-nodejs,guidowb/buildpack-python,andrespires/python-buildpack,drinks/heroku-buildpack-python-scipy,oberlin/heroku-buildpack-python,buildbot/buildbot-master-buildpack,uniphil/heroku-buildpack-pythonsass,Nazanin84/python-buildpack,apiaryio/heroku-buildpack-python-scons,cdht/heroku-buildpack-python,apiaryio/heroku-buildpack-python-scons,ruscoder/heroku-buildpack-python,pmclanahan/heroku-buildpack-python-peep,swanson/heroku-buildpack-python-ortools,andrespires/python-buildpack,Gliimpse/heroku-buildpack-SWIG-python,slorg1/heroku-buildpack-python,jimlindeman/python-buildpack-collectd,HanSooloo/heroku-buildpack-python,pebble/cloudpebble-buildpack,andela-brotich/wger-buildpack-python,Stibbons/heroku-buildpack-python-installer,arnfred/heroku-buildpack-python-hdf5-blas-lapack,nicktimko/heroku-buildpack-scipy,liyanchang/cloudfoundary-buildbot-buildpack,arnaudlimbourg/heroku-buildpack-python,PerceptumNL/heroku-buildpack-python,rajpurkar/heroku-buildpack-python-sklearn,aldryn/heroku-buildpack-python,orablu/heroku-buildpack,amanjain/heroku-buildpack-python-with-django-bower,Nazanin84/python-buildpack,dulaccc/heroku-buildpack-geodjango,agriffis/heroku-buildpack-python,arnfred/heroku-buildpack-python-hdf5-blas-lapack,papaeye/heroku-buildpack-python-bower,codeforamerica/heroku-buildpack-pygeo,dvreed/heroku-buildpack-python-ldap,arnfred/heroku-buildpack-python-hdf5-blas-lapack,orablu/heroku-buildpack,TipWander/heroku-buildpack-geodjango,pkumar-appd/python-buildpack,liyanchang/cloudfoundary-buildbot-buildpack,julienbou/heroku-buildpack-serpan,samuelhavron/heroku-buildpack-python,brightforme/heroku-buildpack-python,loanzen/heroku-buildpack-python,tommyvn/heroku-buildpack-python,rbtying/heroku-buildpack-python,uniphil/heroku-buildpack-pythonsass,samuelhavron/heroku-buildpack-python,ephemerallabs/heroku-buildpack-python,alexflanagan/operand-buildpack-python,Scalingo/python-buildpack,joshowen/heroku-buildpack-python,rawWhipIT/p22-goldant-buildpack,resmio/heroku-buildpack-geodjango,codeforamerica/heroku-buildpack-pygeo,kikin81/heroku-buildpack,heroku/heroku-buildpack-python,skilljar/heroku-buildpack-python,rawWhipIT/p22-goldant-buildpack,rapilabs/heroku-buildpack-python,andrespires/python-buildpack,DylanLukes/heroku-buildpack-python,ianyh/heroku-buildpack-python-opencv,rajpurkar/heroku-buildpack-python-sklearn,Mause/heroku-buildpack-python,kvarga/heroku-buildpack-python,ianyh/heroku-buildpack-python-opencv,joshisa/python-buildpack,ojacobson/heroku-buildpack-python,rajpurkar/heroku-buildpack-python-sklearn,psrthegreat/heroku-buildpack-python-sklearn,rawWhipIT/p22-goldant-buildpack,dbrgn/heroku-buildpack-python-sklearn,vlidholt/heroku-buildpack-scipy,benjaminfox/heroku-buildpack-python-geoip,psrthegreat/heroku-buildpack-python-sklearn,plangrid/heroku-buildpack-python,ianyh/heroku-buildpack-python-nodejs,guidowb/buildpack-python,sjtuadamyang/adamyang-buildpack-python-libjpeg,gitricko/apt-python-buildpack,kowito/python-buildpack,YoApp/heroku-buildpack-python-twemproxy,jvenezia/heroku-buildpack-python,samuelhavron/heroku-buildpack-python,gaumire/heroku-buildpack-python,marcospy/heroku-buildpack-scipy,cortexintel/heroku-buildpack-scipy,xica/heroku-buildpack-scipy,monological/heroku-buildpack-python-opencv,mythmon/heroku-buildpack-python-nodejs,lyft/heroku-buildpack-python-data,Scalingo/python-buildpack,pwdel1/heroku-buildpack-scipy,jms6520/cf-python,mfenniak/heroku-buildpack-python-libffi,cirlabs/heroku-buildpack-geodjango,ianyh/heroku-buildpack-python-nodejs,kowito/python-buildpack,liyanchang/cloudfoundary-buildbot-buildpack,liyanchang/buildbot-master-buildpack,jms6520/cf-python,kennethjiang/heroku-buildpack-python-libffi,WonderThink/heroku-buildpack-python-ffmpeg-geoip,tukutela/heroku-buildpack-python,Brogency/heroku-buildpack-python-gulp,AltSchool/heroku-buildpack-python,aldryn/heroku-buildpack-python,RobertSundling/heroku-buildpack-python-nginx,kikin81/heroku-buildpack,ianyh/heroku-buildpack-python-bower,dbrgn/heroku-npscipy,lyft/heroku-buildpack-python-data,martingascon/heroku-buildpack-python,blazekadam/open2,tukutela/heroku-buildpack-python,zakdoek/heroku-buildpack-django,cirlabs/heroku-buildpack-geodjango,hsr-ba-fs15-dat/heroku-buildpack,uniphil/heroku-buildpack-pythonsass,edmorley/heroku-buildpack-python,stalnacke/heroku-buildpack-python,river-jade/heroku-buildpack-scipy,ianyh/heroku-buildpack-python-opencv,HousekeepLtd/heroku-buildpack-python,Apogaea/heroku-buildpack-python,maciejgryka/heroku-buildpack-spcedge,dbrgn/heroku-buildpack-python-sklearn,pkumar-appd/python-buildpack,alexflanagan/operand-buildpack-python,osharim/-heroku-buildpack-python,smalleats/heroku-buildpack-python,aldryn/heroku-buildpack-python,cloudControl/buildpack-python,film42/heroku-buildpack-python-wkhtmltopdf,18F/python-buildpack,marianzange/heroku-buildpack-python,joshfriend/heroku-buildpack-python,drinks/heroku-buildpack-python-scipy,joshisa/python-buildpack,everysignalinc/heroku-buildpack-python-scikit-learn-git,dubsmash/heroku-buildpack-python,18F/python-buildpack,adamroth/heroku-buildpack-python-pdftk,joshisa/python-buildpack,doda/heroku-buildpack-python,ad-m/heroku-buildpack-python,guidowb/buildpack-python,orablu/heroku-buildpack,heroku/heroku-buildpack-python,lukaszkorecki/heroku-buildpack-python,marcospy/hackathon-globo-app,bobsilverberg/heroku-buildpack-python-peep,film42/heroku-buildpack-python-wkhtmltopdf