Capture installed package information.
Capture installed package information.

The goal is to learn the installed package id of the package we just
installed, as necessary for #1860. We achieve this by inserting an
additional call to "setup register" that produces the installed package
information in a file. We read and parse that file and could now return
the installed package id, but it is not clear what interface would be
appropriate.

bennofs/cabal,gbaz/cabal,martinvlk/cabal,enolan/cabal,rimmington/cabal,thomie/cabal,valderman/cabal,gridaphobe/cabal,corngood/cabal,gbaz/cabal,Helkafen/cabal,sopvop/cabal,Heather/cabal,edsko/cabal,fugyk/cabal,bennofs/cabal,edsko/cabal,lukexi/cabal,mmakowski/cabal,thomie/cabal,typelead/epm,mydaum/cabal,trskop/cabal,plow-technologies/cabal,sopvop/cabal,themoritz/cabal,trskop/cabal,garetxe/cabal,eric-stanley/cabal,themoritz/cabal,christiaanb/cabal,anton-dessiatov/cabal,plow-technologies/cabal,themoritz/cabal,fpco/cabal,lukexi/cabal,x-y-z/cabal,enolan/cabal,randen/cabal,corngood/cabal,thoughtpolice/cabal,kosmikus/cabal,beni55/cabal,thoughtpolice/cabal,anton-dessiatov/cabal,headprogrammingczar/cabal,triplepointfive/cabal,ian-ross/cabal,randen/cabal,sopvop/cabal,rimmington/cabal,x-y-z/cabal,gridaphobe/cabal,fugyk/cabal,christiaanb/cabal,kolmodin/cabal,Helkafen/cabal,plumlife/cabal,beni55/cabal,Peaker/cabal,typelead/epm,Peaker/cabal,valderman/cabal,seereason/cabal,fpco/cabal,mydaum/cabal,mightybyte/cabal,mightybyte/cabal,ghc-android/cabal,garetxe/cabal,headprogrammingczar/cabal,kosmikus/cabal,ghc-android/cabal,kolmodin/cabal,Heather/cabal,seereason/cabal,mmakowski/cabal,eric-stanley/cabal,triplepointfive/cabal,plumlife/cabal,ian-ross/cabal,martinvlk/cabal