[MERGE] Wait for strace to attach before running the function we want to trace

[Martin Pool]

Martin Pool has voted +1.
Status is now: Approved
Comment:
That looks better; it will at least avoid any startup race.

This will possibly get jammed if strace later writes a lot of errors to 
stderr though, since we don't read any more from it.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C20070404014901.GC3690%40steerpike.home.puzzling.org%3E