Append .exe to fix helper lookup in win

Author: jneira

src/CabalHelper/Compiletime/Compile.hs

@@ -134,13 +134,14 @@ compileHelper' CompHelperEnv {..} = do
             ]
   appdir <- appCacheDir
   let cp@CompPaths {compExePath} = compPaths appdir cheProjLocalCacheDir comp
-  helper_exists <- doesFileExist compExePath
+  let compExePathExt = compExePath ++ exeExtension
+  helper_exists <- doesFileExist compExePathExt
   rv <- if helper_exists
     then do
-      vLog $ "helper already compiled, using exe: "++compExePath
+      vLog $ "helper already compiled, using exe: "++compExePathExt
       return (Right compExePath)
     else do
-      vLog $ "helper exe does not exist, compiling "++compExePath
+      vLog $ "helper exe does not exist, compiling "++compExePathExt
       prepare >> compile cp comp
   return rv