diff --git a/build-constraints.yaml b/build-constraints.yaml
index 42199d16..fb8448a4 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -4295,6 +4295,9 @@ packages:
     "Masahiro Honma <hiratara@cpan.org> @hiratara":
         - string-random
 
+    "Michael B. Gale <m.gale@warwick.ac.uk> @mbg":
+        - c14n
+
     "Grandfathered dependencies":
         - network
         - Boolean