integer values do not unpack correctly in prepared stmt

[Wim Lewis]

Integer values returned by drizzle_stmt_get*() are sometimes corrupted. I think the problem is if your char type is signed, then the unpack macros in constants.h will sign-extend less-significant bytes before ORing them into the result. So a SHORT column with a value of 0x1F0 will read back as 0xFFF0.

The non-prepared-statement API doesn't have this problem, presumably because the results are converted to ASCII text by the server.

There's a unit test which shows this problem in http://bazaar.launchpad.net/~wiml/libdrizzle/unit-tests/revision/109 , and a proposed fix in http://bazaar.launchpad.net/~wiml/libdrizzle/integer-sizes/revision/110 .