Makefile: allow building from source without git
Makefile: allow building from source without git

This allows for building from a source tarball/zip using
VERSION=$VERSION make build
abhishekamralkar/prometheus,Conorbro/prometheus,wrouesnel/prometheus,rajthilakmca/prometheus,thachmai/prometheus,msiebuhr/prometheus,mtanda/prometheus,mrwacky42/prometheus,hustbill/prometheus,GoogleCloudPlatform/prometheus,agaoglu/prometheus,dln/prometheus,robbiet480/prometheus,laushinka/prometheus,robbiet480/prometheus,datajet-io/prometheus,PrFalken/prometheus,bluecmd/prometheus,dalanlan/prometheus,laushinka/prometheus,dmilstein/prometheus,fabxc/prometheus,brancz/prometheus,abhishekamralkar/prometheus,amorken/prometheus,tattsun/prometheus,trigrass2/prometheus,AlekSi/prometheus,gesellix/prometheus,nicr9/prometheus,Dieterbe/prometheus,dpatel06/prometheus,slok/prometheus,JavierZunzunegui/prometheus,q3k/prometheus,adamron1/prometheus,tattsun/prometheus,kzittritsch/prometheus,fabxc/prometheus,ton31337/prometheus,jimmidyson/prometheus,gesellix/prometheus,thachmai/prometheus,Conorbro/prometheus,jmcfarlane/prometheus,nicr9/prometheus,PrFalken/prometheus,mtanda/prometheus,AlekSi/prometheus,gesellix/prometheus,fabric8io/prometheus,keegancsmith/prometheus,prasincs/prometheus,gcnonato/prometheus,wrouesnel/prometheus,Gouthamve/prometheus,smyrman/prometheus,wrouesnel/prometheus,Stackdriver/stackdriver-prometheus,abhishekamralkar/prometheus,slok/prometheus,SaltedMan/prometheus-annotated,datajet-io/prometheus,fabxc/prometheus,prometheus/prometheus,brancz/prometheus,brancz/prometheus,q3k/prometheus,tomwilkie/prometheus,dmilstein/prometheus,dln/prometheus,dsymonds/prometheus,prometheus/prometheus,dln/prometheus,sudhi-vm/prometheus,Conorbro/prometheus,laushinka/prometheus,smyrman/prometheus,iksaif/prometheus,smyrman/prometheus,Stackdriver/stackdriver-prometheus,thachmai/prometheus,SaltedMan/prometheus-annotated,fabric8io/prometheus,trigrass2/prometheus,Conorbro/prometheus,trigrass2/prometheus,fabric8io/prometheus,tattsun/prometheus,sudhi-vm/prometheus,prasincs/prometheus,cit-lab/prometheus,cit-lab/prometheus,flier/prometheus,Colstuwjx/prometheus,wxdublin/prometheus,dln/prometheus,tomwilkie/prometheus,q3k/prometheus,kangwoo/prometheus,Colstuwjx/prometheus,amorken/prometheus,PrFalken/prometheus,jmcfarlane/prometheus,gottwald/prometheus,Colstuwjx/prometheus,jbdalido/prometheus,robbiet480/prometheus,keegancsmith/prometheus,wndhydrnt/prometheus,jbdalido/prometheus,hustbill/prometheus,cit-lab/prometheus,fabric8io/prometheus,smyrman/prometheus,prometheus/prometheus,robbiet480/prometheus,rajthilakmca/prometheus,jbdalido/prometheus,kangwoo/prometheus,kangwoo/prometheus,eliothedeman/prometheus,RobertKielty/prometheus,JavierZunzunegui/prometheus,flier/prometheus,AlekSi/prometheus,RobertKielty/prometheus,GoogleCloudPlatform/prometheus,eliothedeman/prometheus,jmcfarlane/prometheus,prometheus/prometheus,mrwacky42/prometheus,wrouesnel/prometheus,dsymonds/prometheus,kzittritsch/prometheus,gcnonato/prometheus,rajthilakmca/prometheus,slok/prometheus,Dieterbe/prometheus,JavierZunzunegui/prometheus,agaoglu/prometheus,mtanda/prometheus,kzittritsch/prometheus,dmilstein/prometheus,trigrass2/prometheus,adamron1/prometheus,prasincs/prometheus,rajthilakmca/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,gottwald/prometheus,hustbill/prometheus,ton31337/prometheus,msiebuhr/prometheus,JavierZunzunegui/prometheus,sudhi-vm/prometheus,kangwoo/prometheus,alileza/prometheus,tomwilkie/prometheus,Gouthamve/prometheus,ton31337/prometheus,yanghongkjxy/prometheus,dpatel06/prometheus,Stackdriver/stackdriver-prometheus,gcnonato/prometheus,wxdublin/prometheus,RobertKielty/prometheus,alileza/prometheus,tomwilkie/prometheus,mtanda/prometheus,dsymonds/prometheus,iksaif/prometheus,laushinka/prometheus,iksaif/prometheus,eliothedeman/prometheus,iksaif/prometheus,yanghongkjxy/prometheus,datajet-io/prometheus,dalanlan/prometheus,thachmai/prometheus,Dieterbe/prometheus,datajet-io/prometheus,adamron1/prometheus,GoogleCloudPlatform/prometheus,dpatel06/prometheus,alileza/prometheus,tattsun/prometheus,eliothedeman/prometheus,RobertKielty/prometheus,wxdublin/prometheus,msiebuhr/prometheus,prasincs/prometheus,mrwacky42/prometheus,jmcfarlane/prometheus,nicr9/prometheus,brancz/prometheus,abhishekamralkar/prometheus,Stackdriver/stackdriver-prometheus,adamron1/prometheus,alileza/prometheus,Gouthamve/prometheus,amorken/prometheus,dmilstein/prometheus,GoogleCloudPlatform/prometheus,AlekSi/prometheus,amorken/prometheus,jbdalido/prometheus,bluecmd/prometheus,flier/prometheus,gesellix/prometheus,agaoglu/prometheus,gcnonato/prometheus,bluecmd/prometheus,Gouthamve/prometheus,cit-lab/prometheus,fabxc/prometheus,wndhydrnt/prometheus,gottwald/prometheus,ton31337/prometheus,yanghongkjxy/prometheus,keegancsmith/prometheus,wndhydrnt/prometheus,bluecmd/prometheus,jimmidyson/prometheus,gottwald/prometheus,hustbill/prometheus,agaoglu/prometheus,q3k/prometheus,alileza/prometheus,SaltedMan/prometheus-annotated,jimmidyson/prometheus,dalanlan/prometheus,Colstuwjx/prometheus,yanghongkjxy/prometheus,SaltedMan/prometheus-annotated,sudhi-vm/prometheus,slok/prometheus,msiebuhr/prometheus,kzittritsch/prometheus,PrFalken/prometheus,dsymonds/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus