Fix typo

Modules/_fileio.c

@@ -591,7 +591,7 @@ portable_lseek(int fd, PyObject *posobj, int whence)
 #if SEEK_CUR != 1
 	case 1: whence = SEEK_CUR; break;
 #endif
-#if SEEL_END != 2
+#if SEEK_END != 2
 	case 2: whence = SEEK_END; break;
 #endif
 	}