🚀 go-pugleaf

This is disturbing news, but I think there's no way to find out why
it happens except by figuring out where in the program the execution
diverges.

It's possible you'll find a GCC bug.  It's also possible that you'll
find an undefined C construct which does different things in 
different compilers.  For example, you might find an expression which
increments a variable and uses that variable another time, such as
`foo (*p, *p++)'.  There is no way a priori to guess the explanation.
It would be pure luck for test cases to help find this; you will
probably get reports of various "failures" in various compilers,
and then there will be no way to draw any conclusion from them.

The easiest way to track down where in the source code the difference
occurs is by running two executables that give different results, both
under debuggers, then doing a binary search with breakpoints to find
the place where the difference happens.