dont output a warning for each boring entry

src/Ignore/Builder.hs

@@ -64,9 +64,7 @@ registerGlob globPattern =
 #ifdef NO_PCRE
 registerRegex :: MonadIO m => T.Text -> CheckerBuilderT m ()
 registerRegex rePattern =
-    CheckerBuilderT $
-    do liftIO $ putStrLn $ "Warning: compile with --without-pcre flag. Ignoring " ++ T.unpack rePattern
-       return ()
+    CheckerBuilderT $ return ()
 #else
 registerRegex :: Monad m => T.Text -> CheckerBuilderT m ()
 registerRegex rePattern =

src/Ignore/VCS/Darcs.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE TemplateHaskell #-}
 module Ignore.VCS.Darcs
     ( makeChecker
@@ -11,8 +12,16 @@ import Control.Monad.Trans
 import Path
 import qualified Data.Text as T
 
+#ifdef NO_PCRE
+makeChecker :: MonadIO m => [T.Text] -> CheckerBuilderT m ()
+makeChecker _ =
+    liftIO $
+    do putStrLn "The ignore library was compiled with the without-pcre flag."
+       putStrLn "This means that we can not handle darcs boring files for now."
+#else
 makeChecker :: MonadIO m => [T.Text] -> CheckerBuilderT m ()
 makeChecker = go
+#endif
 
 file :: Path Rel File
 file = $(mkRelDir "_darcs/prefs") </> $(mkRelFile "boring")

src/Ignore/VCS/Mercurial.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE OverloadedStrings #-}
 module Ignore.VCS.Mercurial
@@ -13,7 +14,14 @@ import Path
 import qualified Data.Text as T
 
 makeChecker :: MonadIO m => [T.Text] -> CheckerBuilderT m ()
-makeChecker = go registerRegex
+makeChecker files =
+    do
+#ifdef NO_PCRE
+       liftIO $
+          do putStrLn "The ignore library was compiled with the without-pcre flag."
+             putStrLn "This means it will only support 'syntax: glob' mercurial blocks"
+#endif
+       go registerRegex files
 
 file :: Path Rel File
 file = $(mkRelFile ".hgignore")