GF.Compile.ReadFiles: a simpler & faster way to convert from Latin1 to UTF-8

src/compiler/GF/Compile/ReadFiles.hs

@@ -232,7 +232,10 @@ toUTF8 opts0 raw =
          coding = getEncoding $ opts0 `addOptions` opts
      utf8 <- if coding=="UTF-8"
              then return raw
-             else lift $ do --ePutStrLn $ "toUTF8 from "++coding
+             else if coding=="CP1252" -- Latin1
+                  then return . UTF8.fromString $ BS.unpack raw -- faster
+                  else lift $
+                       do --ePutStrLn $ "toUTF8 from "++coding
                           enc <- mkTextEncoding coding
                           -- decodeUnicodeIO uses a lot of stack space,
                           -- so we need to split the file into smaller pieces