This patch fixes PR13624, which notes a 64-bit PowerPC ELF ABI

incompatibility with how complex values are returned.  It is sufficient
to flag all complex types as direct rather than indirect.

A new test case is provided that checks correct IR generation for the
various supported flavors of _Complex.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@170302 91177308-0d34-0410-b5e6-96231b3b80d8