clean up FP exception code in sys_float.c
clean up FP exception code in sys_float.c

This performs a number of cleanups in the FP exception code:

- inline the body of unmask_fpe_conditional() in its only caller,
  then delete the duplicated and identical definitions of it

- start the big processor-specific block with a comment describing
  the two functions that must be defined, then delete redundant
  comments at all the mask_*() functions

- add a comment before fpe_sig_action() explaining exactly what
  processor-specific action is required of it

- flatten #ifdef nesting in fpe_sig_action()

- move common code in the x86 unmask_fpe() and erts_restore_fpu()
  function into a subroutine

- minor tweaks: drop a redundant L suffix on a 0, add a comment
  after an #else, bump the size of a debug buffer,

There should be no change in behaviour from these changes.

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