parser: use PyInt_FromSsize_t in index_stats Eliminates mercurial/parsers.c(515) : warning C4244: 'function' : conversion from 'Py_ssize_t' to 'long', possible loss of data mercurial/parsers.c(520) : warning C4244: 'function' : conversion from 'Py_ssize_t' to 'long', possible loss of data mercurial/parsers.c(521) : warning C4244: 'function' : conversion from 'Py_ssize_t' to 'long', possible loss of data when compiling for Windows x64 target using the Microsoft compiler. PyInt_FromSsize_t does not exist for Python 2.4 and earlier, so we define a fallback in util.h to use PyInt_FromLong when compiling for Python 2.4.