Staticized it in userconfig. The one in pcvt is unused.
Removed bogus unused arg to getchar(). This should not have compiled
in the USERCONFIG_BOOT case, but the getchar() was also non-prototyped
and defined in K&R style.
Staticized the badly named global variable `next'. Even static variables
should have a unique module-specific prefix so that they can be referenced
easily in debuggers, etc.