[commit: ghc] master: configure: Throw error if OS is found to be msys (8cfd2e4)

[git at git.haskell.org]

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

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/8cfd2e4e5832bd188816e64daaa95c9003437723/ghc

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

commit 8cfd2e4e5832bd188816e64daaa95c9003437723
Author: Ben Gamari <bgamari.foss at gmail.com>
Date:   Mon Mar 26 15:18:00 2018 -0400

    configure: Throw error if OS is found to be msys
    
    Test Plan: Try running configure on Windows with msys and mingw
    toolchains
    
    Reviewers: Phyx, hvr
    
    Reviewed By: Phyx
    
    Subscribers: rwbarton, thomie, erikd, carter
    
    Differential Revision: https://phabricator.haskell.org/D4526


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

8cfd2e4e5832bd188816e64daaa95c9003437723
 aclocal.m4 | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/aclocal.m4 b/aclocal.m4
index b0a3d44..5b0a679 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1973,6 +1973,9 @@ AC_DEFUN([GHC_CONVERT_OS],[
       freebsd|netbsd|dragonfly|hpux|linuxaout|kfreebsdgnu|freebsd2|mingw32|darwin|nextstep2|nextstep3|sunos4|ultrix|haiku)
         $3="$1"
         ;;
+      msys)
+        AC_MSG_ERROR([Building GHC using the msys toolchain is not supported; please use mingw instead. Perhaps you need to set 'MSYSTEM=MINGW64 or MINGW32?'])
+        ;;
       aix*) # e.g. powerpc-ibm-aix7.1.3.0
         $3="aix"
         ;;