makefile improvements
makefile improvements

ashkan18/eigen,sarahscott/eigen,artsy/eigen,srrvnn/eigen,liduanw/eigen,1aurabrown/eigen,liduanw/eigen,ayunav/eigen,artsy/eigen,srrvnn/eigen,TribeMedia/eigen,srrvnn/eigen,ashkan18/eigen,sarahscott/eigen,orta/eigen,zhuzhengwei/eigen,orta/eigen,foxsofter/eigen,gaurav1981/eigen,neonichu/eigen,artsy/eigen,Shawn-WangDapeng/eigen,ashkan18/eigen,ppamorim/eigen,neonichu/eigen,ichu501/eigen,Shawn-WangDapeng/eigen,mbogh/eigen,neonichu/eigen,ayunav/eigen,gaurav1981/eigen,xxclouddd/eigen,mbogh/eigen,liduanw/eigen,xxclouddd/eigen,Havi4/eigen,srrvnn/eigen,neonichu/eigen,zhuzhengwei/eigen,gaurav1981/eigen,TribeMedia/eigen,Havi4/eigen,TribeMedia/eigen,foxsofter/eigen,zhuzhengwei/eigen,ichu501/eigen,mbogh/eigen,ppamorim/eigen,ayunav/eigen,liduanw/eigen,orta/eigen,Shawn-WangDapeng/eigen,ACChe/eigen,zhuzhengwei/eigen,artsy/eigen,ichu501/eigen,Shawn-WangDapeng/eigen,neonichu/eigen,TribeMedia/eigen,ACChe/eigen,orta/eigen,artsy/eigen,ayunav/eigen,Havi4/eigen,sarahscott/eigen,Havi4/eigen,ACChe/eigen,ashkan18/eigen,xxclouddd/eigen,ACChe/eigen,ichu501/eigen,sarahscott/eigen,ACChe/eigen,srrvnn/eigen,gaurav1981/eigen,1aurabrown/eigen,TribeMedia/eigen,1aurabrown/eigen,1aurabrown/eigen,mbogh/eigen,gaurav1981/eigen,ayunav/eigen,ichu501/eigen,foxsofter/eigen,xxclouddd/eigen,liduanw/eigen,ppamorim/eigen,foxsofter/eigen,xxclouddd/eigen,foxsofter/eigen,ashkan18/eigen,artsy/eigen,Shawn-WangDapeng/eigen,ppamorim/eigen,artsy/eigen