web: fix compilation error with -fblaze_html_0_5 flag

hledger-web/Hledger/Web/Handlers.hs

@@ -52,7 +52,12 @@ import Data.Time.Format
 import System.FilePath (takeFileName)
 import System.IO.Storage (putValue, getValue)
 import System.Locale (defaultTimeLocale)
+#if BLAZE_HTML_0_5
+import Text.Blaze.Internal (preEscapedString)
+import Text.Blaze.Html (toHtml)
+#else
 import Text.Blaze (preEscapedString, toHtml)
+#endif
 import Text.Hamlet hiding (hamlet)
 import Text.Printf
 import Yesod.Core

hledger-web/hledger-web.cabal

@@ -154,6 +154,7 @@ executable         hledger-web
                    , warp
                    , yaml
     if flag(blaze_html_0_5)
+      cpp-options:   -DBLAZE_HTML_0_5
       build-depends:
                      blaze-html               >= 0.5     && < 0.6
                    , blaze-markup             >= 0.5.1   && < 0.6