build-webkit (and other build scripts) should hit setenv commands by default
*most* of the XCode build output is useless setenv commands (duplicated for each call to gcc). build-webkit should grep out this setenv output in a default "not quite so loud" mode. :)
I would do it, but I don't see a slick way of calling system and piping the output through grep. I think the way we'll have to do it is two open2() calls which pipe the output of xcodebuild to grep and the on to STDERR/STDOUT.
The setenv commands are not duplicated for each call to gcc as you claim. I believe they're printed once for each non-compile phase, or something to that effect. If you implement this, please make it easy to disable this filtering as I often use build-webkit to check the values of the Xcode configuration variables, rather than make which always filters them out and is not easily configurable like build-webkit.
What's wrong with doing this?
build-webkit | grep -v setenv