Are you really sure that all the C code the two of you have written in your careers carefully avoids all 191 kinds of undefined behavior in C99 (the number has grown since then)?  Give me leave to doubt it. 

Consider this example from an earlier version of the Linux kernel:

static void __devexit agnx_pci_remove (struct pci_dev *pdev)

Bogus argument.  The Linux kernel is free to rely on specific compiler behavior.