find-grep and complicated patterns

[Lennart Borgman]

find-grep is useful, but a bit hard with complicated patterns. How do 
you for example do something like this:

  find . -name "*.el" -type f -print0 | xargs -0 -e grep -nH -e "aaa bbb"

where there is a space in the pattern? The above does NOT work! Is this 
platform dependent? (On w32 you may use Cygwin or Gnuwin32+cmd.exe here.)