games/keeperrl: unbreak on FreeBSD 10

stdafx.h:94:20: error: redefinition of 'unique'
std::unique_ptr<T> unique(Args&&... args) { return std::unique_ptr<T>(new T(std::forward<Args>(args)...)); }

^

stdafx.h:94:20: note: previous definition is here
std::unique_ptr<T> unique(Args&&... args) { return std::unique_ptr<T>(new T(std::forward<Args>(args)...)); }

^

stack_printer.cpp:329:18: error: assigning to 'char *' from incompatible type 'void *'

ss.ss_sp = (void*)alternate_stack;
           ^~~~~~~~~~~~~~~~~~~~~~