Fix build with llvm trunk.

commit 9f85dccfc64b5f0b0c63ddfa0a42d8615aa1fcb3
Author: Eric Christopher <echristo@gmail.com>
Date:   Mon Aug 4 21:25:23 2014 +0000

    Remove the TargetMachine forwards for TargetSubtargetInfo based
    information and update all callers. No functional change.

    git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214781 91177308-0d34-0410-b5e6-96231b3b80d8

commit f96cd1aeb59f4ee980e370a62020a4ee3da903ec
Author: Saleem Abdulrasool <compnerd@compnerd.org>
Date:   Sat Aug 9 23:12:20 2014 +0000

    ADT: remove MinGW32 and Cygwin OSType enum

    Remove the MinGW32 and Cygwin types from the OSType enumeration.  These values
    are represented via environments of Windows.  It is a source of confusion and
    needlessly clutters the code.  The cost of doing this is that we must sink the
    check for them into the normalization code path along with the spelling.

    Addresses PR20592.

    git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215303 91177308-0d34-0410-b5e6-96231b3b80d8