[commit: ghc] wip/nfs-locking: Filter out repeated ways when copying libffi (b94612d)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : wip/nfs-locking
Link       : http://ghc.haskell.org/trac/ghc/changeset/b94612d33b8febed57d26bc696c9454b883f4aed/ghc

>---------------------------------------------------------------

commit b94612d33b8febed57d26bc696c9454b883f4aed
Author: Andrey Mokhov <andrey.mokhov at gmail.com>
Date:   Fri Jan 13 11:43:58 2017 +0000

    Filter out repeated ways when copying libffi


>---------------------------------------------------------------

b94612d33b8febed57d26bc696c9454b883f4aed
 src/Rules/Libffi.hs | 3 ++-
 src/Way.hs          | 5 ++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/Rules/Libffi.hs b/src/Rules/Libffi.hs
index 0f703d9..99b77c8 100644
--- a/src/Rules/Libffi.hs
+++ b/src/Rules/Libffi.hs
@@ -56,7 +56,8 @@ libffiRules = do
                 copyFile header (rtsBuildPath -/- takeFileName header)
 
             ways <- interpretInContext libffiContext (getLibraryWays <> getRtsWays)
-            forM_ ways $ \way -> copyFile libffiLibrary =<< rtsLibffiLibrary way
+            forM_ (nubOrd ways) $ \way ->
+                copyFile libffiLibrary =<< rtsLibffiLibrary way
 
             putSuccess $ "| Successfully built custom library 'libffi'"
 
diff --git a/src/Way.hs b/src/Way.hs
index 22ae6fa8..cb73f04 100644
--- a/src/Way.hs
+++ b/src/Way.hs
@@ -24,7 +24,7 @@ data WayUnit = Threaded
              | Profiling
              | Logging
              | Dynamic
-             deriving (Eq, Enum, Bounded)
+             deriving (Bounded, Enum, Eq, Ord)
 
 -- TODO: get rid of non-derived Show instances
 instance Show WayUnit where
@@ -74,6 +74,9 @@ instance Read Way where
 instance Eq Way where
     Way a == Way b = a == b
 
+instance Ord Way where
+    compare (Way a) (Way b) = compare a b
+
 -- | Build default _vanilla_ way.
 vanilla :: Way
 vanilla = wayFromUnits []