Fix Makefile to not ignore xref return code
Fix Makefile to not ignore xref return code

platinumthinker/rebar,platinumthinker/rebar,oubiwann/rebar,choptastic/rebar,matwey/rebar,sile/rebar3,macintux/rebar,lrascao/rebar3,beni55/rebar-1,norton/rebar,scatterbrain/rebar,oubiwann/rebar,apache/couchdb-rebar,bsmr-erlang/rebar,djnym/rebar3,cloudant/couchdb-rebar,shkumagai/rebar,K2InformaticsGmbH/rebar,cloudant/couchdb-rebar,paulo-ferraz-oliveira/rebar,evnix/rebar,K2InformaticsGmbH/rebar,linearregression/rebar3,jbalint/rebar3,lrascao/rebar,saleyn/rebar3,walrusVision/rebar3,processone/rebar3,beni55/rebar-1,syl20bnr/rebar,paulo-ferraz-oliveira/rebar,heroku/rebar,beni55/rebar,walrusVision/rebar3,jbalint/rebar3,GabrielNicolasAvellaneda/rebar,fabiankrol/rebar3,heroku/rebar,K2InformaticsGmbH/rebar,csyangchen/rebar,cloudant/couchdb-rebar,zugolosian/rebar3,GabrielNicolasAvellaneda/rebar,wcy123/rebar,matwey/rebar,jacktang/rebar,benoitc/rebar3,basho/rebar,lpgauth/rebar,K2InformaticsGmbH/rebar,project-fifo/rebar3,RubberCthulhu/rebar,blt/rebar3,rebar/rebar,zugolosian/rebar3,wcy123/rebar,fauxsoup/rebar3,CMoH/rebar,choptastic/rebar,syl20bnr/rebar,rebar/rebar,fabiankrol/rebar3,thomasbhatia/rebar,GabrielNicolasAvellaneda/rebar,choptastic/rebar,norton/rebar,project-fifo/rebar3,SiDen/rebar,RubberCthulhu/rebar,SiDen/rebar,lpgauth/rebar,dcarastan/rebar,shkumagai/rebar,rebar/rebar,scatterbrain/rebar,evnix/rebar,CMoH/rebar,paulo-ferraz-oliveira/rebar,syl20bnr/rebar,kellymclaughlin/rebar3,norton/rebar,oubiwann/rebar,linearregression/rebar3,fauxsoup/rebar3,bsmr-erlang/rebar,apache/couchdb-rebar,macintux/rebar,surik/rebar3,lpgauth/rebar,shkumagai/rebar,fishcakez/rebar3,beni55/rebar,beni55/rebar,lrascao/rebar,tsloughter/rebar3,rebar/rebar3,platinumthinker/rebar,bsmr-erlang/rebar,norton/rebar3,sile/rebar3,blt/rebar3,dcarastan/rebar,surik/rebar3,deadok22/rebar,erlang/rebar3,lrascao/rebar,apache/couchdb-rebar,norton/rebar,csyangchen/rebar,evnix/rebar,vladdu/rebar3,K2InformaticsGmbH/rebar,bsmr-erlang/rebar,benoitc/rebar3,processone/rebar3,matwey/rebar,basho/rebar,ferd/rebar3,csyangchen/rebar,CMoH/rebar,scatterbrain/rebar,jacktang/rebar,macintux/rebar,lrascao/rebar,lrascao/rebar,deadok22/rebar,thomasbhatia/rebar,matwey/rebar,thomasbhatia/rebar,SiDen/rebar,dcarastan/rebar,matwey/rebar,jacktang/rebar,rebar/rebar3