bdiff: use Py_ssize_t instead of int Reduces the conversion warnings mercurial/bdiff.c(61) : warning C4244: '=' : conversion from '__int64' to 'int', possible loss of data mercurial/bdiff.c(307) : warning C4244: 'function' : conversion from 'Py_ssize_t' to 'int', possible loss of data mercurial/bdiff.c(308) : warning C4244: 'function' : conversion from 'Py_ssize_t' to 'int', possible loss of data mercurial/bdiff.c(362) : warning C4244: '+=' : conversion from '__int64' to 'int', possible loss of data mercurial/bdiff.c(380) : warning C4244: '=' : conversion from '__int64' to 'int', possible loss of data mercurial/bdiff.c(381) : warning C4244: 'function' : conversion from '__int64' to 'uint32_t', possible loss of data mercurial/bdiff.c(382) : warning C4244: 'function' : conversion from '__int64' to 'uint32_t', possible loss of data mercurial/bdiff.c(416) : warning C4244: '=' : conversion from 'Py_ssize_t' to 'int', possible loss of data to mercurial/bdiff.c(383) : warning C4244: 'function' : conversion from '__int64' to 'uint32_t', possible loss of data mercurial/bdiff.c(384) : warning C4244: 'function' : conversion from '__int64' to 'uint32_t', possible loss of data mercurial/bdiff.c(385) : warning C4244: 'function' : conversion from 'Py_ssize_t' to 'uint32_t', possible loss of data on the three putbe32() calls in the function bdiff when compiling for Windows x64 target using the Microsoft compiler.