AST: Properly calculate the linkage of a IndirectFieldDecl

getLVForNamespaceScopeDecl believed that it wasn't possible for it to
ever see an IndirectFieldDecl.  However, this can occur when determining
whether or not something is a redeclaration of a member of an anonymous
static union.

This fixes PR21858.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@223975 91177308-0d34-0410-b5e6-96231b3b80d8
Revert the default changing behavior part of r216662 until we
can change the backend to be the same default. Leave the
modified/new testcases with the exception of the default behavior
since it increases our testing footprint.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@223976 91177308-0d34-0410-b5e6-96231b3b80d8
Add a FIXME for unifying ARM target abi handling.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@223977 91177308-0d34-0410-b5e6-96231b3b80d8