--- src/Text/CSL/Input/Bibutils.hs	2014-05-05 04:58:55.000000000 +0200
+++ src/Text/CSL/Input/Bibutils.hs	2014-07-13 01:27:29.051215204 +0200
@@ -63,6 +63,7 @@
                               "using the file extension."
 #else
         _           -> error $ "citeproc: Bibliography format not supported.\n" ++
+                              "using the file extension."
 #endif
 
 data BibFormat
--- pandoc-citeproc.hs	2014-07-13 01:44:05.324283005 +0200
+++ pandoc-citeproc.hs	2014-07-13 01:41:42.838273308 +0200
@@ -74,6 +74,7 @@
   where go "biblatex" = Just BibLatex
         go "bib"      = Just BibLatex
         go "bibtex"   = Just Bibtex
+#ifdef USE_BIBUTILS
         go "ris"      = Just Ris
         go "endnote"  = Just Endnote
         go "enl"      = Just Endnote
@@ -83,6 +84,7 @@
         go "isi"      = Just Isi
         go "medline"  = Just Medline
         go "copac"    = Just Copac
+#endif
         go "json"     = Just Json
         go _          = Nothing
 
--- pandoc-citeproc.cabal	2014-07-13 02:03:06.072360638 +0200
+++ pandoc-citeproc.cabal	2014-07-13 02:04:19.907365662 +0200
@@ -324,6 +324,10 @@
 executable pandoc-citeproc
     main-is:          pandoc-citeproc.hs
     hs-source-dirs:   .
+    default-extensions: CPP
+    if flag(bibutils)
+        build-depends:   hs-bibutils >= 0.3
+        cpp-options:     -DUSE_BIBUTILS
     ghc-options:      -funbox-strict-fields -Wall
     ghc-prof-options: -prof -auto-all
     build-depends:    base >= 4, pandoc-citeproc, pandoc-types >= 1.12.3, aeson,