.func emits debugging information to denote function name, and
is ignored unless the file is assembled with debugging enabled.
Only `--gstabs[+]' is currently supported.
label is the entry point of the function and if omitted name
prepended with the `leading char' is used.
`leading char' is usually
_ or nothing, depending on the target.
All functions are currently defined to have
void return type.
The function must be terminated with