NetBSD uses signed wchar_t on AArch64. It also wants __LITTLE_ENDIAN__ /
__BIG_ENDIAN__ as on other architectures.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@200655 91177308-0d34-0410-b5e6-96231b3b80d8
Test pre-defined macros of aarch64-netbsd.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@200656 91177308-0d34-0410-b5e6-96231b3b80d8