Fix #27877: writing .avi files > 4 GB not working on windows.

Solution is to replace "long" by "int64_t" and "fseek" by "_fseeki64", because
long on 64 bit windows is still 32 bit.

source/gameengine/Ketsji/KX_PythonInit.cpp

@@ -327,7 +327,7 @@ static PyObject* gPyLoadGlobalDict(PyObject*)
 {
 	char marshal_path[512];
 	char *marshal_buffer = NULL;
-	unsigned int marshal_length;
+	size_t marshal_length;
 	FILE *fp = NULL;
 	int result;
 
@@ -338,7 +338,7 @@ static PyObject* gPyLoadGlobalDict(PyObject*)
 	if (fp) {
 		// obtain file size:
 		fseek (fp, 0, SEEK_END);
-		marshal_length = ftell(fp);
+		marshal_length = (size_t)ftell(fp);
 		rewind(fp);
 
 		marshal_buffer = (char*)malloc (sizeof(char)*marshal_length);