fix c comment syntax
we're talking -O3, aren't we?
hand written C version using mmap, almost 3x faster

timings on my macbook:

me$ cc -O3 query_t1gram2.hand.c; time ./a.out ~/Downloads/googlebooks-eng-all-1gram-20120701-a

real	0m8.925s
user	0m8.395s
sys	0m0.472s

me$ cc -O3 query_t1gram2.hand2.c; time ./a.out ~/Downloads/googlebooks-eng-all-1gram-20120701-a

real	0m3.110s
user	0m1.501s
sys	0m1.590s