diff --git a/build-constraints.yaml b/build-constraints.yaml
index fc459fcd..f8517d9b 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -20,6 +20,8 @@ packages:
         - arrowp-qq
         - clr-marshal
         - clr-host
+        - hp2pretty # With permission of Claude Heiland-Allend
+        - floatshow # https://bitbucket.org/dafis/floatshow/issues/1/add-to-stackage
         - threepenny-editors
         - clr-inline  # possibly nondeterministic failures, see https://github.com/fpco/stackage/issues/2510