Make the spy tool compilation fail with a useful error message if you try to compile it to any architecture other than x64

[defuse]

From an email I received, it currently fails with an error like...

gcc -c flushreload.c -o flushreload.o
In file included from flushreload.c:12:0:
flushreload.c: In function ‘attackLoop’:
attacktools.h:57:5: error: inconsistent operand constraints in an ‘asm’
     asm __volatile__(
     ^
attacktools.h:57:5: error: inconsistent operand constraints in an ‘asm’
     asm __volatile__(
     ^
attacktools.h:57:5: error: inconsistent operand constraints in an ‘asm’
     asm __volatile__(

...which is absolutely useless for determining what the problem is.