Fix a 'not a normal file' error when compressing large files.

The bzip2 command line would report 'not a normal file' for files of
size larger than 2^32 - 1 bytes.

Patch bzip2.c to use _stati64 instead of _stat so that a successful
result is returned for large files.

Resolves https://github.com/philr/bzip2-windows/issues/3.
diff --git a/bzip2.c b/bzip2.c
index be3b3be..76c6c94 100644
--- a/bzip2.c
+++ b/bzip2.c
@@ -132,8 +132,8 @@
 
 #   define NORETURN       /**/
 #   define PATH_SEP       '\\'
-#   define MY_LSTAT       _stat
-#   define MY_STAT        _stat
+#   define MY_LSTAT       _stati64
+#   define MY_STAT        _stati64
 #   define MY_S_ISREG(x)  ((x) & _S_IFREG)
 #   define MY_S_ISDIR(x)  ((x) & _S_IFDIR)