peek at passed gcc arguments on build and run

If I have a correct understanding of what you're trying to achieve:
compile with -v -Wall

This will give you a verbose output of everything the compiler is doing.

 

"Show Log Navigator" (command-7), click on one of the "Build" items, switch on "All" instead of "Recent" and "All Messages", click on the line that built an item you are interested in, and expand with the "multi-line" symbol on the right.