--- /dev/null
+Fails to build with -f-bibutils:
+https://bugs.gentoo.org/516640
+diff --git a/pandoc-citeproc.hs b/pandoc-citeproc.hs
+index 7006e02..f72fa41 100644
+--- a/pandoc-citeproc.hs
++++ b/pandoc-citeproc.hs
+@@ -1 +1,2 @@
++{-# LANGUAGE CPP #-}
+ module Main where
+@@ -75,2 +76,3 @@ readFormat = go . map toLower
+ go "bibtex" = Just Bibtex
++#ifdef USE_BIBUTILS
+ go "ris" = Just Ris
+@@ -87,2 +89,3 @@ readFormat = go . map toLower
+ go "yaml" = Just Yaml
++#endif
+ go _ = Nothing
+diff --git a/src/Text/CSL/Input/Bibutils.hs b/src/Text/CSL/Input/Bibutils.hs
+index 081fa91..49ddbd0 100644
+--- a/src/Text/CSL/Input/Bibutils.hs
++++ b/src/Text/CSL/Input/Bibutils.hs
+@@ -64,3 +64,3 @@ readBiblioFile f
+ #else
+- _ -> error $ "citeproc: Bibliography format not supported.\n" ++
++ _ -> error $ "citeproc: Bibliography format not supported.\n"
+ #endif