mpatch: use Py_ssize_t Eliminates mpatch.c(73) : warning C4244: 'return' : conversion from '__int64' to 'int', possible loss of data mpatch.c(299) : warning C4244: 'function' : conversion from 'Py_ssize_t' to 'int', possible loss of data mpatch.c(321) : warning C4244: '=' : conversion from 'Py_ssize_t' to 'int', possible loss of data mpatch.c(335) : warning C4244: 'function' : conversion from 'Py_ssize_t' to 'int', possible loss of data mpatch.c(346) : warning C4244: 'function' : conversion from 'Py_ssize_t' to 'int', possible loss of data when compiling for Windows x64 target using the Microsoft compiler.