MC: rework static_assert to be MSVC compatible

Visual Studio does not permit referencing a structure member as a static field
for sizeof calculations.  Resort to a pointer cast which is compatible across
Visual Studio and other compilers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206445 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed