Was playing around with Stefan's git hook for checkpatch.pl: http://blog.vmsplice.net/2011/03/how-to-automatically-run-checkpatchpl.html
which seems really useful butter-finger coders such as myself. But some of warnings/errors that have carried over from the kernel have made this approach somewhat prohibitive for QEMU code. These patches add a flag that let's checkpatch.pl exit successfully when we only have warnings, while still printing them and encouraging users to fix them. We also make C99 //comments a warning instead of an error, since they don't actually violate QEMU's coding guidelines.
