manually copy the "c-runtime" branch from the old repository.

src/compiler/GF/CompileInParallel.hs

@@ -1,6 +1,6 @@
 -- | Parallel grammar compilation
 module GF.CompileInParallel(parallelBatchCompile) where
-import Prelude hiding (catch,(<>)) -- GHC 8.4.1 clash with Text.PrettyPrint
+import Prelude hiding (catch)
 import Control.Monad(join,ap,when,unless)
 import Control.Applicative
 import GF.Infra.Concurrency
@@ -34,11 +34,8 @@ import qualified Data.ByteString.Lazy as BS
 parallelBatchCompile jobs opts rootfiles0 =
   do setJobs jobs
      rootfiles <- mapM canonical rootfiles0
-     lib_dirs1 <- getLibraryDirectory opts
-     lib_dirs2 <- mapM canonical lib_dirs1
-     let lib_dir = head lib_dirs2
-     when (length lib_dirs2 >1) $ ePutStrLn ("GF_LIB_PATH defines more than one directory; using the first, " ++ show lib_dir)
-     filepaths <- mapM (getPathFromFile [lib_dir] opts) rootfiles
+     lib_dir  <- canonical =<< getLibraryDirectory opts
+     filepaths <- mapM (getPathFromFile lib_dir opts) rootfiles
      let groups = groupFiles lib_dir filepaths
          n = length groups
      when (n>1) $ ePutStrLn "Grammar mixes present and alltenses, dividing modules into two groups"