Fix for integer overflow bug in binary search.

[dpsi]

Performing arithmetic on 2 keys can lead to signed integer overflow/underflow in the binary search algorithm. The result can lead to keys not being found or being inserted in the wrong place. This bug was caught using UBSAN.

The masking of most significant bit in key generation routines should also be reconsidered:

lbtree/keygen-8B/keygen.c

Line 28 in 92f7304

return (((a<<32)^(b<<16)^(c)) & (0x7FFFFFFFFFFFFFFFLL));

lbtree/common/keyinput.h

Line 191 in 92f7304

return (((a<<32)^(b<<16)^(c)) & (0x7FFFFFFFFFFFFFFFLL));