[commit: ghc] master: ghc-bin.cabal.in: add a 'threaded' flag for hadrian (99eb459)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/99eb4595910f20c41734aa07a2da4db1f25512ae/ghc

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

commit 99eb4595910f20c41734aa07a2da4db1f25512ae
Author: Alp Mestanogullari <alp at well-typed.com>
Date:   Mon Oct 1 15:14:23 2018 +0200

    ghc-bin.cabal.in: add a 'threaded' flag for hadrian
    
    Summary:
    hadrian will explicitly enable this flag, but more importantly needs it
    as otherwise we just never end up passing -threaded to GHC when building
    a new GHC binary. We could quite likely unconditionally pass -threaded,
    as the corresponding logic for GhcThreaded in mk/config.mk.in seems to
    always lead to it being set to True, but we instead leave a way out for
    anyone in need of a GHC linked against a non-threaded runtime system in
    the future.
    
    Test Plan: T8242 (with a GHC built by hadrian)
    
    Reviewers: bgamari
    
    Reviewed By: bgamari
    
    Subscribers: rwbarton, carter
    
    Differential Revision: https://phabricator.haskell.org/D5146


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

99eb4595910f20c41734aa07a2da4db1f25512ae
 ghc/ghc-bin.cabal.in | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/ghc/ghc-bin.cabal.in b/ghc/ghc-bin.cabal.in
index 5c51058..1f15c34 100644
--- a/ghc/ghc-bin.cabal.in
+++ b/ghc/ghc-bin.cabal.in
@@ -24,6 +24,11 @@ Flag ghci
     Default: False
     Manual: True
 
+Flag threaded
+    Description: Link the ghc executable against the threaded RTS
+    Default: True
+    Manual: True
+
 Executable ghc
     Default-Language: Haskell2010
 
@@ -80,6 +85,13 @@ Executable ghc
             UnboxedTuples
             ViewPatterns
 
+    -- The flag being True by default, this reflects the
+    -- mk/config.mk.in logic for GhcThreaded (which ends up
+    -- always being True as well). One can still opt out by
+    -- disabling this flag.
+    if flag(threaded)
+      ghc-options: -threaded
+
     Other-Extensions:
         CPP
         NondecreasingIndentation