guile: 2.2.0 -> 2.2.3

2.2.3: https://lists.gnu.org/archive/html/guile-devel/2017-12/msg00000.html
2.2.2: https://lists.gnu.org/archive/html/guile-devel/2017-04/msg00035.html
2.2.1: https://lists.gnu.org/archive/html/guile-devel/2017-04/msg00034.html