Ugly band-aid to work around a bug in Linux ftell().

Objects/fileobject.c

@@ -421,6 +421,8 @@ new_buffersize(f, currentsize)
 	struct stat st;
 	if (fstat(fileno(f->f_fp), &st) == 0) {
 		end = st.st_size;
+		pos = lseek(fileno(f->f_fp), 0L, SEEK_CUR);
+		if (pos >= 0)
 			pos = ftell(f->f_fp);
 		if (pos < 0)
 			clearerr(f->f_fp);