epp: Refactor expansion of header path
epp: Refactor expansion of header path

scan_include_lib/4 uses a helper function find_lib_dir/1, which has a
strange interface. It takes a string and returns a tuple. The caller
must match the tuple and call fname_join/1 to obtain the desired
result. I assume that the strange interface was not noticed because
the function is only used in one place.

Replace the find_lib_dir/1 with a new expand_lib_dir/1 function which
does the entire job in one go. The new function is much easier to
reuse in other places, which we might want to do in a future commit.

potatosalad/otp,vladdu/otp,fenollp/otp,psyeugenic/otp,fenollp/otp,kvakvs/otp,lightcyphers/otp,dumbbell/otp,getong/otp,saleyn/otp,getong/otp,dumbbell/otp,goertzenator/otp,electricimp/otp,uabboli/otp,lightcyphers/otp,dgud/otp,ahmedshafeeq/otp,bjorng/otp,emacsmirror/erlang,neeraj9/otp,bjorng/otp,psyeugenic/otp,erlang/otp,bjorng/otp,bsmr-erlang/otp,saleyn/otp,emile/otp,bernardd/otp,g-andrade/otp,RoadRunnr/otp,RoadRunnr/otp,falkevik/otp,legoscia/otp,saleyn/otp,basho/otp,tuncer/otp,tuncer/otp,massemanet/otp,dgud/otp,release-project/otp,vladdu/otp,falkevik/otp,isvilen/otp,aboroska/otp,jj1bdx/otp,emile/otp,saleyn/otp,ahmedshafeeq/otp,RaimoNiskanen/otp,basho/otp,legoscia/otp,lemenkov/otp,ferd/otp,bjorng/otp,ferd/otp,bsmr-erlang/otp,matwey/otp,bjorng/otp,mikpe/otp,erlang/otp,RoadRunnr/otp,vladdu/otp,dumbbell/otp,psyeugenic/otp,dumbbell/otp,electricimp/otp,electricimp/otp,vinoski/otp,isvilen/otp,dumbbell/otp,release-project/otp,bugs-erlang-org/otp,potatosalad/otp,ferd/otp,dgud/otp,potatosalad/otp,dumbbell/otp,bernardd/otp,ferd/otp,getong/otp,basho/otp,fenollp/otp,g-andrade/otp,electricimp/otp,erlang/otp,goertzenator/otp,fenollp/otp,release-project/otp,fenollp/otp,aboroska/otp,mikpe/otp,lightcyphers/otp,bsmr-erlang/otp,getong/otp,potatosalad/otp,rlipscombe/otp,lrascao/otp,matwey/otp,lrascao/otp,emacsmirror/erlang,vinoski/otp,bjorng/otp,RaimoNiskanen/otp,RaimoNiskanen/otp,bugs-erlang-org/otp,vinoski/otp,legoscia/otp,RoadRunnr/otp,kvakvs/otp,g-andrade/otp,goertzenator/otp,rlipscombe/otp,bugs-erlang-org/otp,basho/otp,release-project/otp,g-andrade/otp,bugs-erlang-org/otp,isvilen/otp,psyeugenic/otp,getong/otp,matwey/otp,electricimp/otp,RoadRunnr/otp,massemanet/otp,rlipscombe/otp,ferd/otp,mikpe/otp,tuncer/otp,bjorng/otp,bernardd/otp,getong/otp,vinoski/otp,legoscia/otp,release-project/otp,kvakvs/otp,vinoski/otp,rlipscombe/otp,ahmedshafeeq/otp,emile/otp,saleyn/otp,goertzenator/otp,fenollp/otp,rlipscombe/otp,falkevik/otp,uabboli/otp,neeraj9/otp,electricimp/otp,matwey/otp,isvilen/otp,saleyn/otp,bugs-erlang-org/otp,ferd/otp,massemanet/otp,vladdu/otp,erlang/otp,massemanet/otp,bsmr-erlang/otp,bugs-erlang-org/otp,weisslj/otp,RaimoNiskanen/otp,fenollp/otp,vinoski/otp,tuncer/otp,emile/otp,bernardd/otp,legoscia/otp,RaimoNiskanen/otp,rlipscombe/otp,rlipscombe/otp,jj1bdx/otp,matwey/otp,isvilen/otp,lrascao/otp,massemanet/otp,kvakvs/otp,lemenkov/otp,jj1bdx/otp,jj1bdx/otp,massemanet/otp,kvakvs/otp,erlang/otp,falkevik/otp,dgud/otp,potatosalad/otp,lemenkov/otp,mikpe/otp,g-andrade/otp,erlang/otp,weisslj/otp,jj1bdx/otp,emacsmirror/erlang,ahmedshafeeq/otp,matwey/otp,bugs-erlang-org/otp,uabboli/otp,legoscia/otp,cobusc/otp,rlipscombe/otp,RaimoNiskanen/otp,lemenkov/otp,getong/otp,aboroska/otp,getong/otp,cobusc/otp,isvilen/otp,lrascao/otp,aboroska/otp,emile/otp,bernardd/otp,bsmr-erlang/otp,electricimp/otp,dgud/otp,neeraj9/otp,kvakvs/otp,lightcyphers/otp,RoadRunnr/otp,erlang/otp,massemanet/otp,ahmedshafeeq/otp,emacsmirror/erlang,bernardd/otp,potatosalad/otp,fenollp/otp,bsmr-erlang/otp,dumbbell/otp,release-project/otp,dumbbell/otp,weisslj/otp,emacsmirror/erlang,massemanet/otp,getong/otp,psyeugenic/otp,neeraj9/otp,potatosalad/otp,lrascao/otp,jj1bdx/otp,bjorng/otp,saleyn/otp,release-project/otp,legoscia/otp,uabboli/otp,kvakvs/otp,cobusc/otp,weisslj/otp,electricimp/otp,psyeugenic/otp,mikpe/otp,vladdu/otp,g-andrade/otp,psyeugenic/otp,RoadRunnr/otp,uabboli/otp,goertzenator/otp,lemenkov/otp,lemenkov/otp,ferd/otp,bsmr-erlang/otp,vladdu/otp,vladdu/otp,uabboli/otp,rlipscombe/otp,emacsmirror/erlang,lightcyphers/otp,cobusc/otp,bernardd/otp,g-andrade/otp,vinoski/otp,emile/otp,weisslj/otp,falkevik/otp,goertzenator/otp,isvilen/otp,dgud/otp,kvakvs/otp,fenollp/otp,matwey/otp,dumbbell/otp,dumbbell/otp,release-project/otp,mikpe/otp,cobusc/otp,aboroska/otp,emile/otp,falkevik/otp,emile/otp,bsmr-erlang/otp,electricimp/otp,falkevik/otp,weisslj/otp,g-andrade/otp,RaimoNiskanen/otp,goertzenator/otp,falkevik/otp,isvilen/otp,lemenkov/otp,mikpe/otp,uabboli/otp,ahmedshafeeq/otp,ahmedshafeeq/otp,RaimoNiskanen/otp,tuncer/otp,ahmedshafeeq/otp,aboroska/otp,weisslj/otp,potatosalad/otp,RaimoNiskanen/otp,emacsmirror/erlang,saleyn/otp,vinoski/otp,bernardd/otp,lrascao/otp,g-andrade/otp,dgud/otp,neeraj9/otp,erlang/otp,legoscia/otp,massemanet/otp,bugs-erlang-org/otp,basho/otp,bernardd/otp,erlang/otp,psyeugenic/otp,emacsmirror/erlang,RoadRunnr/otp,neeraj9/otp,RoadRunnr/otp,aboroska/otp,aboroska/otp,neeraj9/otp,kvakvs/otp,mikpe/otp,legoscia/otp,emile/otp,mikpe/otp,tuncer/otp,goertzenator/otp,lightcyphers/otp,matwey/otp,jj1bdx/otp,basho/otp,vladdu/otp,jj1bdx/otp,lemenkov/otp,erlang/otp,g-andrade/otp,getong/otp,vladdu/otp,jj1bdx/otp,saleyn/otp,isvilen/otp,cobusc/otp,emacsmirror/erlang,aboroska/otp,dgud/otp,uabboli/otp,vinoski/otp,tuncer/otp,weisslj/otp,tuncer/otp,uabboli/otp,matwey/otp,goertzenator/otp,lightcyphers/otp,potatosalad/otp,dgud/otp,cobusc/otp,basho/otp,isvilen/otp,lrascao/otp,ahmedshafeeq/otp,weisslj/otp,lightcyphers/otp,jj1bdx/otp,tuncer/otp,bjorng/otp,cobusc/otp,ferd/otp,falkevik/otp,basho/otp,basho/otp,ferd/otp,lrascao/otp,rlipscombe/otp,bjorng/otp,release-project/otp,potatosalad/otp,vinoski/otp,lrascao/otp,dgud/otp,bsmr-erlang/otp,mikpe/otp,emacsmirror/erlang,neeraj9/otp