Update time submodule to v1.6 release

This is the designated release to go with GHC 8.0.1

/cc @AshleyYakeley

compiler/ghc.cabal.in

@@ -49,7 +49,7 @@ Library
                    process    >= 1   && < 1.5,
                    bytestring >= 0.9 && < 0.11,
                    binary     == 0.8.*,
-                   time                 < 1.6,
+                   time       >= 1.4 && < 1.7,
                    containers >= 0.5 && < 0.6,
                    array      >= 0.1 && < 0.6,
                    filepath   >= 1   && < 1.5,

Cabal @ 50ccb668

-Subproject commit e275a162ccac087f8b25b424551e8a1598dd5943
+Subproject commit 50ccb668e866ccbe35a1982bf81750cec7aea382

directory @ 5696798a

-Subproject commit 4dcb2873166558575fe70142da87952bd558f943
+Subproject commit 5696798a0adbf3401688f223fe64a4aa6378e87b

hpc @ a6dee685

-Subproject commit 5123582f48b46efc3d27424bc475125a1de78e2e
+Subproject commit a6dee68551ce931e2d2184c47c0e64180618450a

time @ 409d7a01

-Subproject commit 8d3c90a420c8985dcc439766c028821cea7dc848
+Subproject commit 409d7a01659c2ac331017a6ece423485bc7aaf01

unix @ 4f3b5d8b

-Subproject commit 5d5b74716b696b0f22c37a88ccc5c114b13f0398
+Subproject commit 4f3b5d8b87eef07d8df62a8d7240830bb81a8a6b

mk/warnings.mk

@@ -55,9 +55,7 @@ libraries/vector_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports
 # haddock's attoparsec uses deprecated `inlinePerformIO`
 utils/haddock_dist_EXTRA_HC_OPTS += -Wno-deprecations
 
-# not yet de-tabbed
-libraries/time_dist-install_EXTRA_HC_OPTS += -Wno-tabs
-# On Windows, there are also some unused import warnings
+# On Windows, there are/were some unused import warnings
 ifeq "$(HostOS_CPP)" "mingw32"
 libraries/time_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports -Wno-identities
 endif