shells/ast-ksh: Mark BROKEN on 14

Fails to compile with:
error: incompatible function pointer types assigning to 'int (*)(wchar_t
*, const char *, size_t)' (aka 'int (*)(int *, const char *, unsigned
long)') from 'size_t (wchar_t *, const char *, size_t)' (aka 'unsigned
long (int *, const char *, unsigned long)')
[-Wincompatible-function-pointer-types]

Approved by: portmgr (blanket)
Sponsored by: The FreeBSD Foundation