os: point readers at the exec package
os: point readers at the exec package

R=golang-dev, evan, rsc
CC=golang-dev
http://codereview.appspot.com/4802046

scirelli/scirelli-go,rdp/rogerpack2005-golang,npe9/noahevans-go9,webfd/go-zh,mhennings/marcohennings-go,npe9/noahevans-go9,bryanxu/go-zh,glycerine/jeaten-go-arrayof-structof,bryanxu/go-zh,glycerine/jeaten-go-arrayof-structof,Triskite/willstone-goclone,d0f/go-zh,scirelli/scirelli-go,webfd/go-zh,bryanxu/go-zh,mhennings/marcohennings-go,sanjosh/sanjos100-tipc,sanjosh/sanjos100-tipc,rflanagan/reginaldflanagan-project1,webfd/go-zh,Triskite/willstone-goclone,glycerine/jeaten-go-arrayof-structof,sanjosh/sanjos100-tipc,rdp/rogerpack2005-golang,sanjosh/sanjos100-tipc,rdp/rogerpack2005-golang,rflanagan/reginaldflanagan-project1,Triskite/willstone-goclone,webfd/go-zh,rdp/rogerpack2005-golang,bryanxu/go-zh,mhennings/marcohennings-go,scirelli/scirelli-go,mhennings/marcohennings-go,rflanagan/reginaldflanagan-project1,npe9/noahevans-go9,webfd/go-zh,rdp/rogerpack2005-golang,Triskite/willstone-goclone,bryanxu/go-zh,mhennings/marcohennings-go,scirelli/scirelli-go,rdp/rogerpack2005-golang,bryanxu/go-zh,scirelli/scirelli-go,glycerine/jeaten-go-arrayof-structof,scirelli/scirelli-go,bryanxu/go-zh,npe9/noahevans-go9,webfd/go-zh,rflanagan/reginaldflanagan-project1,rflanagan/reginaldflanagan-project1,webfd/go-zh,npe9/noahevans-go9,mhennings/marcohennings-go,glycerine/jeaten-go-arrayof-structof,webfd/go-zh,scirelli/scirelli-go,mhennings/marcohennings-go,npe9/noahevans-go9,sanjosh/sanjos100-tipc,bryanxu/go-zh,glycerine/jeaten-go-arrayof-structof,d0f/go-zh,rdp/rogerpack2005-golang,Triskite/willstone-goclone,d0f/go-zh,d0f/go-zh,npe9/noahevans-go9,npe9/noahevans-go9,rflanagan/reginaldflanagan-project1,mhennings/marcohennings-go,sanjosh/sanjos100-tipc,d0f/go-zh,rflanagan/reginaldflanagan-project1,Triskite/willstone-goclone,Triskite/willstone-goclone,d0f/go-zh,Triskite/willstone-goclone,sanjosh/sanjos100-tipc,rflanagan/reginaldflanagan-project1,sanjosh/sanjos100-tipc,glycerine/jeaten-go-arrayof-structof,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,rdp/rogerpack2005-golang,scirelli/scirelli-go,d0f/go-zh