prefer qhull_p shared libraries over libqhull
prefer qhull_p shared libraries over libqhull

upstream added libqhull_p.so in version 2012 which is compiled
_with_ -Dqh_QHpointer and changed libqhull.so to use -Dqh_QHpointer=0.

Only debian/ubuntu doesn't acknowledge this and still provides
libqhull.so with -Dqh_QHpointer=1.

Before this change PCL+QHULL_USE_STATIC=0 compiled with -Dqh_QHpointer,
but always linked libqhull.so. As explained this is the wrong choice on
qhull 2012 with non-debian systems.

Closes #410

nikste/pcl,Tabjones/pcl,cascheberg/pcl,RufaelDev/pcc-mp3dg,stfuchs/pcl,DaikiMaekawa/pcl,RufaelDev/pcc-mp3dg,v4hn/pcl,simonleonard/pcl,kanster/pcl,v4hn/pcl,sbec/pcl,KevenRing/vlp,starius/pcl,v4hn/pcl,KevenRing/vlp,shivmalhotra/pcl,starius/pcl,stfuchs/pcl,sbec/pcl,nikste/pcl,shyamalschandra/pcl,shivmalhotra/pcl,ResByte/pcl,chenxingzhe/pcl,DaikiMaekawa/pcl,the-glu/pcl,shangwuhencc/pcl,3dtof/pcl,ipa-rmb/pcl,Tabjones/pcl,krips89/pcl_newfeatures,RufaelDev/pcc-mp3dg,stefanbuettner/pcl,wgapl/pcl,kanster/pcl,pkuhto/pcl,shangwuhencc/pcl,locnx1984/pcl,closerbibi/pcl,lydhr/pcl,stefanbuettner/pcl,stefanbuettner/pcl,simonleonard/pcl,3dtof/pcl,stefanbuettner/pcl,msalvato/pcl_kinfu_highres,fanxiaochen/mypcltest,stfuchs/pcl,ipa-rmb/pcl,KevenRing/pcl,kanster/pcl,closerbibi/pcl,fanxiaochen/mypcltest,fskuka/pcl,locnx1984/pcl,3dtof/pcl,lebronzhang/pcl,jakobwilm/pcl,stfuchs/pcl,fanxiaochen/mypcltest,raydtang/pcl,LZRS/pcl,raydtang/pcl,ResByte/pcl,chatchavan/pcl,fanxiaochen/mypcltest,raydtang/pcl,kanster/pcl,drmateo/pcl,locnx1984/pcl,soulsheng/pcl,jakobwilm/pcl,damienjadeduff/pcl,ResByte/pcl,LZRS/pcl,v4hn/pcl,ResByte/pcl,kanster/pcl,MMiknis/pcl,drmateo/pcl,mschoeler/pcl,shivmalhotra/pcl,jakobwilm/pcl,drmateo/pcl,ResByte/pcl,fskuka/pcl,cascheberg/pcl,shangwuhencc/pcl,lydhr/pcl,simonleonard/pcl,lydhr/pcl,the-glu/pcl,cascheberg/pcl,drmateo/pcl,KevenRing/vlp,KevenRing/vlp,shyamalschandra/pcl,soulsheng/pcl,zhangxaochen/pcl,damienjadeduff/pcl,sbec/pcl,fskuka/pcl,LZRS/pcl,closerbibi/pcl,starius/pcl,nikste/pcl,the-glu/pcl,lebronzhang/pcl,MMiknis/pcl,shyamalschandra/pcl,mikhail-matrosov/pcl,stfuchs/pcl,mikhail-matrosov/pcl,lebronzhang/pcl,RufaelDev/pcc-mp3dg,msalvato/pcl_kinfu_highres,lebronzhang/pcl,fskuka/pcl,soulsheng/pcl,Tabjones/pcl,DaikiMaekawa/pcl,chatchavan/pcl,mikhail-matrosov/pcl,pkuhto/pcl,raydtang/pcl,wgapl/pcl,shyamalschandra/pcl,closerbibi/pcl,fanxiaochen/mypcltest,krips89/pcl_newfeatures,damienjadeduff/pcl,nikste/pcl,mikhail-matrosov/pcl,locnx1984/pcl,DaikiMaekawa/pcl,shivmalhotra/pcl,fskuka/pcl,wgapl/pcl,sbec/pcl,drmateo/pcl,soulsheng/pcl,zhangxaochen/pcl,starius/pcl,chenxingzhe/pcl,cascheberg/pcl,KevenRing/pcl,Tabjones/pcl,chatchavan/pcl,pkuhto/pcl,stefanbuettner/pcl,zhangxaochen/pcl,mschoeler/pcl,zhangxaochen/pcl,KevenRing/pcl,jakobwilm/pcl,soulsheng/pcl,3dtof/pcl,jakobwilm/pcl,LZRS/pcl,msalvato/pcl_kinfu_highres,closerbibi/pcl,Tabjones/pcl,ipa-rmb/pcl,DaikiMaekawa/pcl,raydtang/pcl,chenxingzhe/pcl,zhangxaochen/pcl,chenxingzhe/pcl,lebronzhang/pcl,locnx1984/pcl,the-glu/pcl,ipa-rmb/pcl,shangwuhencc/pcl,krips89/pcl_newfeatures,msalvato/pcl_kinfu_highres,simonleonard/pcl,v4hn/pcl,krips89/pcl_newfeatures,simonleonard/pcl,MMiknis/pcl,wgapl/pcl,nikste/pcl,mschoeler/pcl,pkuhto/pcl,RufaelDev/pcc-mp3dg,ipa-rmb/pcl,MMiknis/pcl,cascheberg/pcl,starius/pcl,damienjadeduff/pcl,sbec/pcl,damienjadeduff/pcl,pkuhto/pcl,lydhr/pcl,shivmalhotra/pcl,MMiknis/pcl,mikhail-matrosov/pcl,KevenRing/pcl,shyamalschandra/pcl,KevenRing/pcl,chenxingzhe/pcl,lydhr/pcl,mschoeler/pcl,krips89/pcl_newfeatures,mschoeler/pcl,chatchavan/pcl,wgapl/pcl,msalvato/pcl_kinfu_highres,shangwuhencc/pcl,the-glu/pcl,3dtof/pcl,KevenRing/vlp,LZRS/pcl